kt_jvm_grpc_library errors if the .proto file does not contain a service

[blockjon-dd]

I wrote some automation that builds .proto files into GRPC clients in different languages. I just noticed that kt_jvm_grpc_library fails if the .proto file does not happen to contain a service. The Bazel rules for other languages do not error when this is the case and therefore I think that kt_jvm_grpc_library should probably also not fail like I'm seeing it fail.

Example error:

$ bazel build //protos/public/dv/v1:dv_v1_go_proto_kotlin_grpc_library
INFO: Analyzed target //protos/public/dv/v1:dv_v1_go_proto_kotlin_grpc_library (0 packages loaded, 0 targets configured).
ERROR: /workspaces/myapp/protos/public/dv/v1/BUILD.bazel:13:13: Generating Kotlin gRPC srcjar for @@//protos/public/dv/v1:dv_v1_proto failed: (Exit 255): zipper failed: error executing KtGrpcSrcJar command (from target //protos/public/dv/v1:dv_v1_go_proto_kotlin_grpc_library_DO_NOT_DEPEND_kt_grpc) external/bazel_tools/tools/zip/zipper/zipper c bazel-out/aarch64-fastbuild/bin/protos/public/dv/v1/dv_v1_go_proto_kotlin_grpc_library_DO_NOT_DEPEND_kt_grpc.srcjar

Use --sandbox_debug to see verbose messages from the sandbox and retain the sandbox build root for debugging
Can't create zip without input files specified.Target //protos/public/dv/v1:dv_v1_go_proto_kotlin_grpc_library failed to build
Use --verbose_failures to see the command lines of failed build steps.
INFO: Elapsed time: 1.084s, Critical Path: 0.87s
INFO: 10 processes: 6 remote cache hit, 4 internal.
ERROR: Build did NOT complete successfully