impl(generator): handle deprecated services

[scotthart]

v29 of protobuf adds [[deprecated]] attributes to proto message types generated from deprecated services. We need to disable compiler warnings on these types because of -Werror until we remove the deprecated services.

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This change is 

[codecov]

Codecov Report

Attention: Patch coverage is 51.88172% with 179 lines in your changes missing coverage. Please review.

Project coverage is 93.00%. Comparing base (000bb23) to head (cb3c9f3).
Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
...s/golden/v1/internal/deprecated_connection_impl.cc	28.57%	15 Missing ⚠️
...den/v1/internal/deprecated_rest_connection_impl.cc	0.00%	15 Missing ⚠️
.../v1/internal/deprecated_rest_metadata_decorator.cc	0.00%	14 Missing ⚠️
...n_tests/golden/v1/internal/deprecated_rest_stub.cc	0.00%	14 Missing ⚠️
...golden/v1/internal/deprecated_rest_stub_factory.cc	0.00%	13 Missing ⚠️
...ests/golden/v1/internal/deprecated_tracing_stub.cc	0.00%	12 Missing ⚠️
...olden/v1/internal/deprecated_metadata_decorator.cc	42.10%	11 Missing ⚠️
...ntegration_tests/golden/v1/deprecated_connection.h	58.33%	10 Missing ⚠️
...tion_tests/golden/v1/deprecated_rest_connection.cc	0.00%	10 Missing ⚠️
...olden/v1/internal/deprecated_tracing_connection.cc	25.00%	9 Missing ⚠️
... and 18 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #14849      +/-   ##
==========================================
- Coverage   93.07%   93.00%   -0.08%     
==========================================
  Files        2319     2351      +32     
  Lines      209109   209479     +370     
==========================================
+ Hits       194630   194824     +194     
- Misses      14479    14655     +176     

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[dbolduc]

In the long run, I think we want to deprecate these clients. As in GOOGLE_CLOUD_CPP_DEPRECATED(...).

[dbolduc]

nit: remove this line?

[scotthart]

Done.

[scotthart]

Good idea. I went ahead an added it to the generated Client.

Reviewable status: 0 of 113 files reviewed, all discussions resolved (waiting on @dbolduc)

[scotthart]

Done.