feat(o11y): regenerate stubs with lro_stub_options enabled

[haphungw]

Regenerate all client stubs to include the LRO options parameters in the generated Stub trait methods.

[gemini-code-assist]

Code Review

This pull request updates the generator configuration in librarian.yaml to enable LRO stub options and bumps the library version, resulting in regenerated client SDKs. These regenerated files introduce conditional support for unstable tracing (google_cloud_unstable_tracing) to record LRO polling attributes and propagate poller options. Additionally, several service READMEs are updated with descriptive overviews. The feedback highlights that the description_override for the google-cloud-longrunning crate was unintentionally removed in librarian.yaml and should be restored to preserve crates.io metadata and historical context.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.87%. Comparing base (3185f7a) to head (219d0e7).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5880      +/-   ##
==========================================
- Coverage   97.88%   97.87%   -0.01%     
==========================================
  Files         230      230              
  Lines       58106    58106              
==========================================
- Hits        56877    56874       -3     
- Misses       1229     1232       +3     

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