Resolve Python logger warnings
Author: emmanuel-ferdman
Pull request: yes

# What does this PR do?

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This small PR resolves the annoying deprecation warnings of the `logger` library:
```python
DeprecationWarning: The 'warn' method is deprecated, use 'warning' instead
```



## Before submitting
- [ ] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
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      Pull Request section?
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      [here are tips on formatting docstrings](https://github.com/huggingface/transformers/tree/main/docs#writing-source-documentation).
- [ ] Did you write any new necessary tests?


## Who can review?

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Comments:
@bot /style

Style fixes have been applied. [View the workflow run here](https://github.com/huggingface/transformers/actions/runs/15112831170).

The docs for this PR live [here](https://moon-ci-docs.huggingface.co/docs/transformers/pr_38183). All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.