impl(generator): add synchronous LRO method on stubs and decorators

[scotthart]

part of the work for #7658

This PR adds the stub methods and decorator overrides for calling the grpc plugin generated stub synchronous method for LRO rpcs. The PR is split into multiple commits to separate the generator changes, tests for the golden generated code, and all the generated code updates.

---

This change is 

[codecov]

Codecov Report

Attention: Patch coverage is 80.94535% with 129 lines in your changes missing coverage. Please review.

Project coverage is 93.19%. Comparing base (12fad74) to head (c24aee0).
Report is 2 commits behind head on main.

Files	Patch %	Lines
...den/v1/internal/golden_thing_admin_tracing_stub.cc	0.00%	35 Missing ⚠️
...olden/v1/internal/request_id_metadata_decorator.cc	0.00%	16 Missing ⚠️
...ternal/golden_thing_admin_round_robin_decorator.cc	0.00%	10 Missing ⚠️
...ests/golden/v1/internal/request_id_tracing_stub.cc	0.00%	8 Missing ⚠️
...ests/golden/v1/internal/golden_thing_admin_stub.cc	80.00%	7 Missing ⚠️
...ration_tests/golden/v1/internal/request_id_stub.cc	0.00%	7 Missing ⚠️
...n/v1/internal/golden_thing_admin_auth_decorator.cc	80.00%	5 Missing ⚠️
...ts/golden/v1/internal/request_id_auth_decorator.cc	0.00%	5 Missing ⚠️
...ator/internal/metadata_decorator_rest_generator.cc	0.00%	5 Missing ⚠️
...1/internal/golden_thing_admin_logging_decorator.cc	80.00%	4 Missing ⚠️
... and 13 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #14341      +/-   ##
==========================================
- Coverage   93.23%   93.19%   -0.05%     
==========================================
  Files        2183     2183              
  Lines      191523   192192     +669     
==========================================
+ Hits       178564   179110     +546     
- Misses      12959    13082     +123     

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

[coryan]

Reviewed 2326 of 2326 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @scotthart)