feat(generator): surface actionable error on unsupported resumable upload transport configs

[whowes]

Updates generated HttpJson[Service]ResumableUploadStub.create() to detect customized gRPC transport configurations via HttpJsonCallableFactory.isResumableUploadSupported(). When one is detected, the stub wires upload methods to HttpJsonCallableFactory.createFailingResumableUploadCallable() so client initialization and standard gRPC RPCs still succeed while upload calls fail with an informative IllegalStateException.

[gemini-code-assist]

Code Review

This pull request updates the resumable upload stub generation and implementation to check if resumable upload is supported, returning a failing callable if it is not. It refactors the stub constructors to accept the callables and background resources directly rather than instantiating them internally, and updates the generator class HttpJsonServiceResumableUploadStubClassComposer accordingly. Feedback on the generator suggests passing resumableUploadMethods to createConstructorMethods and iterating over them to ensure the generated constructor parameter order deterministically matches the argument order in createStaticCreatorMethods, rather than relying on the iteration order of callableClassMembers.values().

[sonarqubecloud]

Quality Gate passed for 'gapic-generator-java-root'

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
98.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[sonarqubecloud]

Quality Gate failed for 'gapic-generator-java-root'

Failed conditions
0.0% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud