feat(protoc_plugin): use Fully-qualified service name even for Non-gRPC Service (e.g. `greet.v1.GreetService`)

[utamori]

The process for obtaining the service name is different Whether the grpc option is enabled.

I want to call rpc with the full service name, even when grpc is not used.
Should I add a new option?

protobuf.dart/protoc_plugin/lib/src/grpc_generator.dart

Lines 36 to 43 in ccf104d

	GrpcServiceGenerator(this._descriptor, this.fileGen) {
	final name = _descriptor.name;
	final package = fileGen.package;
	if (package.isNotEmpty) {
	_fullServiceName = '$package.$name';
	} else {
	_fullServiceName = name;

protobuf.dart/protoc_plugin/lib/src/client_generator.dart

Lines 34 to 39 in ccf104d

	ClientApiGenerator(
	this.service, Set<String> usedNames, this._repeatedFieldIndex)
	: className = disambiguateName(
	avoidInitialUnderscore(service._descriptor.name),
	usedNames,
	defaultSuffixes());