chore: make Haystack warnings consistent

[anakin87]

Related Issues

Across our codebase, we mostly use logging.warning but sometimes we also use warnings.warn.

We have decided to:

• use logging.warning
• use warnings.warn (DeprecationWarning) only for deprecations

Proposed Changes:

• replace warnings.warn with logging.warning (taking also care of structured logging)

How did you test it?

CI; adapted some tests on warnings

Checklist

• I have read the contributors guidelines and the code of conduct
• I have updated the related issue with new insights and changes
• I added unit tests and updated the docstrings
• I've used one of the conventional commit types for my PR title: fix:, feat:, build:, chore:, ci:, docs:, style:, refactor:, perf:, test: and added ! in case the PR includes breaking changes.
• I documented my code
• I ran pre-commit hooks and fixed any issue

[coveralls]

Pull Request Test Coverage Report for Build 13974248160

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 37 unchanged lines in 7 files lost coverage.
• Overall coverage decreased (-0.005%) to 90.012%

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Files with Coverage Reduction	New Missed Lines	%
components/converters/output_adapter.py	1	98.48%
components/embedders/hugging_face_api_text_embedder.py	1	97.1%
components/embedders/hugging_face_api_document_embedder.py	2	96.59%
components/evaluators/llm_evaluator.py	2	94.96%
components/readers/extractive.py	3	95.69%
components/routers/conditional_router.py	12	85.94%
evaluation/eval_run_result.py	16	62.37%

Totals
Change from base Build 13971804559:	-0.005%
Covered Lines:	9814
Relevant Lines:	10903

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💛 - Coveralls

[mpangrazzi]

Looks good! Will probably do the same in Hayhooks.