chore: update code to be compatible with protobuf v36

[scotthart]

No description provided.

[gemini-code-assist]

Code Review

This pull request upgrades the Protobuf dependency to version 36.0-rc2 across Bazel configurations, Dockerfiles, and workspace files, and casts several Protobuf method calls to (void) to ignore their return values. The reviewer feedback correctly notes that casting any.UnpackTo(&result) to (void) in extract_long_running_result.cc silently swallows unpacking errors, violating the repository's 'Demand Explosive Correctness' principle, and suggests returning an error status if unpacking fails.

[gemini-code-assist]

Silently ignoring the return value of UnpackTo by casting it to (void) swallows potential errors when unpacking the operation metadata. If unpacking fails, we should return an appropriate error status instead of proceeding with a success status, in accordance with the repository style guide's 'Demand Explosive Correctness' principle.

  if (!any.UnpackTo(&result)) {
    return Status(StatusCode::kInvalidArgument,
                  "Failed to unpack operation metadata in operation " + op->name(),
                  GCP_ERROR_INFO());
  }
  return Status{};

References

1. Never swallow errors or ignore Status types. Fail loudly and explicitly when appropriate. ^(link)

[gemini-code-assist]

Silently ignoring the return value of UnpackTo by casting it to (void) swallows potential errors when unpacking the operation response. If unpacking fails, we should return an appropriate error status instead of proceeding with a success status, in accordance with the repository style guide's 'Demand Explosive Correctness' principle.

  if (!any.UnpackTo(&result)) {
    return Status(StatusCode::kInvalidArgument,
                  "Failed to unpack operation response in operation " + op->name(),
                  GCP_ERROR_INFO());
  }
  return Status{};

References

1. Never swallow errors or ignore Status types. Fail loudly and explicitly when appropriate. ^(link)

[codecov]

Codecov Report

❌ Patch coverage is 91.00000% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 92.23%. Comparing base (154f9ef) to head (b852f97).
⚠️ Report is 6 commits behind head on main.

Files with missing lines	Patch %	Lines
google/cloud/spanner/samples/samples.cc	0.00%	6 Missing ⚠️
generator/internal/descriptor_utils.cc	50.00%	1 Missing ⚠️
google/cloud/pubsub/samples/samples.cc	0.00%	1 Missing ⚠️
...cloud/spanner/testing/database_integration_test.cc	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #16342      +/-   ##
==========================================
- Coverage   92.23%   92.23%   -0.01%     
==========================================
  Files        2227     2227              
  Lines      209283   209275       -8     
==========================================
- Hits       193026   193017       -9     
- Misses      16257    16258       +1     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.