feat(bigquery): drop Python 3.7-3.9 support and regenerate

[chalmerlowe]

Updates post processing to account for dropping support for Python 3.7, 3.8, 3.9 and the impacts that has on using 3.10 for lower bounds testing.

Changes

• Resolved Build & Environment Issues: Bumped pandas, pyarrow, and opentelemetry constraints to versions providing native Python 3.10 wheels and avoiding pkg_resources failures.
• Refactored EOL Checks: Standardised the warning logic using sys.version_info < (3, 10) directly.
• Deleted Redundant Helpers: Cleanly removed the custom helper extract_runtime_version() and unused sys and _versions_helpers imports.
• Aligned Protobuf: Standardised protobuf==4.25.8 to align with the GAPIC templates and the rest of the library families.
• Updated post-processing scripts to ensure the above updates pers

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[gemini-code-assist]

Code Review

This pull request enables code generation for the google-cloud-bigquery library by removing the skip_generate flag in librarian.yaml. Feedback indicates that several metadata fields were removed from .repo-metadata.json which should be restored to maintain consistency for documentation generation and library discovery.