Is your feature request related to a problem? Please describe.

@grpc/grpc-js has multiple advantages over grpc. All Google libraries are now switching to @grpc/grpc-js. This is the only library left that I still see a dependency on grpc, which is use only in tests and as a source of type definitions.

Describe the solution you'd like

I'd like to see the dependency dropped and the source code to either use type definitions from google-gax or @grpc/grpc-js.

Describe alternatives you've considered

I don't see alternatives.

Additional context

Not applicable.