chore: update to librarian v0.31.2-0.20260730143954-e9da697881de

[parthea]

This pull request bumps the Librarian version to v0.31.2-0.20260730143954-e9da697881de

All of the changes in 3f323c8 were created by this command

docker run -u $(id -u):$(id -g) -v .:/repo -v ~/.cache:/.cache -w /repo docker.io/library/librarian-python:e9da697881de7de6ebf9e5b17ef6704a4c0dbc52 generate -v --all

[parthea]

This is ok for google-cloud-python. Historically, we have been checking in gencode and will continue to do so.

[gemini-code-assist]

Code Review

This pull request updates generated protocol buffer files across multiple packages to support Protobuf Python Version 6.33.5 (upgraded from 4.25.3). The changes include adding runtime version validation, replacing deprecated _options with _loaded_options, updating boolean descriptor checks to use pythonic not, and modernizing type annotations in .pyi files (such as using collections.abc for Iterable and Mapping, and adding datetime support). Additionally, test configurations have been updated to include the new edition field. There are no review comments, and we have no feedback to provide.