ci(python): ignore deprecated hf_xet.download_files warning

[westonpace]

Summary

• test_write_hf_dataset is failing on macOS and Windows CI because huggingface_hub's Xet download path calls the now-deprecated hf_xet.download_files(), and python/pyproject.toml configures pytest with error::DeprecationWarning.
• The deprecation lives in huggingface_hub itself (file_download.py:558), not in Lance — huggingface_hub has not yet migrated to the new XetSession().new_file_download_group().start_download_file() API.
• Add a narrow filterwarnings ignore for that exact message, matching the existing pattern used for other third-party deprecation noise (boto3, pytorch, distutils, etc.).

Failing CI message:

DeprecationWarning: hf_xet.download_files() is deprecated.
Use XetSession().new_file_download_group().start_download_file() instead.
huggingface_hub/file_download.py:558: DeprecationWarning

The ignore is scoped to the exact message, so any other DeprecationWarning still escalates to a test failure as before. When huggingface_hub migrates to the XetSession API, this entry can be removed.

Test plan

• CI: test_write_hf_dataset passes on macOS and Windows runners
• Other DeprecationWarning-as-error coverage is unchanged (filter only matches the hf_xet.download_files() message)

🤖 Generated with Claude Code

[claude]

Claude Code Review

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[westonpace]

Upstream issue for tracking: huggingface/huggingface_hub#4195