Fix AttributeError on missing use_sft in grain data processing

[bvandermoon]

Description

Fixes an AttributeError: 'types.SimpleNamespace' object has no attribute 'use_sft' in make_grain_eval_iterator caused by a collision between PR #4754 and PR #4625.

• In src/maxtext/input_pipeline/grain_data_processing.py, safely check use_sft, use_dpo, and use_multimodal with getattr(config, ..., False) in _get_pipeline_fn, make_grain_train_iterator, and make_grain_eval_iterator.
• In tests/unit/mmap_data_processing_test.py, define use_sft=False and use_multimodal=False in GrainMmapNpyEvalConfigTest._config.

Tests

• pytest tests/unit/mmap_data_processing_test.py -k "GrainMmapNpyEvalConfigTest" passes.
• All 161 tests in tests/unit/mmap_data_processing_test.py pass.

Checklist

Before submitting this PR, please make sure (put X in square brackets):

• I have performed a self-review of my code. For an optional AI review, add the gemini-review label.
• I have necessary comments in my code, particularly in hard-to-understand areas.
• I have run end-to-end tests tests and provided workload links above if applicable.
• I have made or will make corresponding changes to the doc if needed, including adding new documentation pages to the relevant Table of Contents (toctree directive) as explained in our documentation.

[gemini-code-assist]

Code Review

This pull request updates the input pipeline data processing code to use getattr with default values when accessing configuration attributes like use_sft, use_multimodal, use_dpo, train_image_column, and eval_image_column. This prevents potential AttributeError exceptions when these configuration options are not explicitly defined. Additionally, default values for use_sft and use_multimodal were added to the test configuration helper. There are no review comments, so I have no feedback to provide.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 7 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...rc/maxtext/input_pipeline/grain_data_processing.py	0.00%	7 Missing ⚠️

📢 Thoughts on this report? Let us know!