[Enhancement] Replace warnings.warn with print_log

[HAOCHENYE]

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Motivation

Replace warnings.warn with print_log in some modules to avoid throwing duplicated warnings during DDP training. The basic rules are:

1. Those warnings could be raised in DDP training.
2. Functions that throw these warnings will not be called repeatedly during training.

The original warning caused by dataset:

/home/yehaochen/codebase/mmengine/mmengine/runner/loops.py:56: UserWarning: Dataset CIFAR10 has no metainfo. ``dataset_meta`` in visualizer will be None.
  warnings.warn(
/home/yehaochen/codebase/mmengine/mmengine/runner/loops.py:56: UserWarning: Dataset CIFAR10 has no metainfo. ``dataset_meta`` in visualizer will be None.
  warnings.warn(
/home/yehaochen/codebase/mmengine/mmengine/runner/loops.py:56: UserWarning: Dataset CIFAR10 has no metainfo. ``dataset_meta`` in visualizer will be None.
  warnings.warn(
/home/yehaochen/codebase/mmengine/mmengine/evaluator/metric.py:47: UserWarning: The prefix is not set in metric class Accuracy.
  warnings.warn('The prefix is not set in metric class '
/home/yehaochen/codebase/mmengine/mmengine/evaluator/metric.py:47: UserWarning: The prefix is not set in metric class Accuracy.
  warnings.warn('The prefix is not set in metric class '
/home/yehaochen/codebase/mmengine/mmengine/runner/loops.py:335: UserWarning: Dataset CIFAR10 has no metainfo. ``dataset_meta`` in evaluator, metric and visualizer will be None.
  warnings.warn(
/home/yehaochen/codebase/mmengine/mmengine/runner/loops.py:335: UserWarning: Dataset CIFAR10 has no metainfo. ``dataset_meta`` in evaluator, metric and visualizer will be None.
  warnings.warn(
/home/yehaochen/codebase/mmengine/mmengine/evaluator/metric.py:47: UserWarning: The prefix is not set in metric class Accuracy.
  warnings.warn('The prefix is not set in metric class '
/home/yehaochen/codebase/mmengine/mmengine/runner/loops.py:335: UserWarning: Dataset CIFAR10 has no metainfo. ``dataset_meta`` in evaluator, metric and visualizer will be None.
  warnings.warn(
/home/yehaochen/codebase/mmengine/mmengine/runner/loops.py:56: UserWarning: Dataset CIFAR10 has no metainfo. ``dataset_meta`` in visualizer will be None.
  warnings.warn(
/home/yehaochen/codebase/mmengine/mmengine/runner/loops.py:56: UserWarning: Dataset CIFAR10 has no metainfo. ``dataset_meta`` in visualizer will be None.
  warnings.warn(
/home/yehaochen/codebase/mmengine/mmengine/runner/loops.py:56: UserWarning: Dataset CIFAR10 has no metainfo. ``dataset_meta`` in visualizer will be None.
  warnings.warn(
/home/yehaochen/codebase/mmengine/mmengine/runner/loops.py:56: UserWarning: Dataset CIFAR10 has no metainfo. ``dataset_meta`` in visualizer will be None.
  warnings.warn(
/home/yehaochen/codebase/mmengine/mmengine/runner/loops.py:56: UserWarning: Dataset CIFAR10 has no metainfo. ``dataset_meta`` in visualizer will be None.
  warnings.warn(
/home/yehaochen/codebase/mmengine/mmengine/evaluator/metric.py:47: UserWarning: The prefix is not set in metric class Accuracy.
  warnings.warn('The prefix is not set in metric class '
/home/yehaochen/codebase/mmengine/mmengine/runner/loops.py:335: UserWarning: Dataset CIFAR10 has no metainfo. ``dataset_meta`` in evaluator, metric and visualizer will be None.
  warnings.warn(
/home/yehaochen/codebase/mmengine/mmengine/evaluator/metric.py:47: UserWarning: The prefix is not set in metric class Accuracy.
  warnings.warn('The prefix is not set in metric class '
/home/yehaochen/codebase/mmengine/mmengine/runner/loops.py:335: UserWarning: Dataset CIFAR10 has no metainfo. ``dataset_meta`` in evaluator, metric and visualizer will be None.
  warnings.warn(
/home/yehaochen/codebase/mmengine/mmengine/evaluator/metric.py:47: UserWarning: The prefix is not set in metric class Accuracy.
  warnings.warn('The prefix is not set in metric class '
/home/yehaochen/codebase/mmengine/mmengine/evaluator/metric.py:47: UserWarning: The prefix is not set in metric class Accuracy.
  warnings.warn('The prefix is not set in metric class '
/home/yehaochen/codebase/mmengine/mmengine/runner/loops.py:335: UserWarning: Dataset CIFAR10 has no metainfo. ``dataset_meta`` in evaluator, metric and visualizer will be None.
  warnings.warn(
/home/yehaochen/codebase/mmengine/mmengine/runner/loops.py:335: UserWarning: Dataset CIFAR10 has no metainfo. ``dataset_meta`` in evaluator, metric and visualizer will be None.
  warnings.warn(
/home/yehaochen/codebase/mmengine/mmengine/evaluator/metric.py:47: UserWarning: The prefix is not set in metric class Accuracy.
  warnings.warn('The prefix is not set in metric class '
/home/yehaochen/codebase/mmengine/mmengine/runner/loops.py:335: UserWarning: Dataset CIFAR10 has no metainfo. ``dataset_meta`` in evaluator, metric and visualizer will be None.
  warnings.warn(

The optimized one:

03/06 16:50:53 - mmengine - WARNING - Dataset CIFAR10 has no metainfo. ``dataset_meta`` in visualizer will be None.
03/06 16:50:53 - mmengine - WARNING - The prefix is not set in metric class Accuracy.
03/06 16:50:53 - mmengine - WARNING - Dataset CIFAR10 has no metainfo. ``dataset_meta`` in evaluator, metric and visualizer will be None.
03/06 16:50:53 - mmengine - WARNING - "FileClient" will be deprecated in future. Please use io functions in https://mmengine.readthedocs.io/en/latest/api/fileio.html#file-io
03/06 16:50:53 - mmengine - WARNING - "HardDiskBackend" is the alias of "LocalBackend" and the former will be deprecated in future.

Modification

Please briefly describe what modification is made in this PR.

BC-breaking (Optional)

Does the modification introduce changes that break the backward-compatibility of the downstream repos?
If so, please describe how it breaks the compatibility and how the downstream projects should modify their code to keep compatibility with this PR.

Use cases (Optional)

If this PR introduces a new feature, it is better to list some use cases here, and update the documentation.

Checklist

1. Pre-commit or other linting tools are used to fix the potential lint issues.
2. The modification is covered by complete unit tests. If not, please add more unit test to ensure the correctness.
3. If the modification has potential influence on downstream projects, this PR should be tested with downstream projects, like MMDet or MMCls.
4. The documentation has been modified accordingly, like docstring or example tutorials.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (main@7e1b273). Click here to learn what that means.
Patch has no changes to coverable lines.

❗ Current head ba9cb36 differs from pull request most recent head aa38ef7. Consider uploading reports for the commit aa38ef7 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #961   +/-   ##
=======================================
  Coverage        ?   76.53%           
=======================================
  Files           ?      138           
  Lines           ?    10855           
  Branches        ?     2167           
=======================================
  Hits            ?     8308           
  Misses          ?     2188           
  Partials        ?      359           

Flag	Coverage Δ
unittests	76.53% <0.00%> (?)

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