Incompatible with validators

Tested with both `github.com/mwitkow/go-proto-validators` and `github.com/envoyproxy/protoc-gen-validate/`, it all failed with `File not found` errors.

This is caused by these validators lib not registering themselves into reflection. However, these protos are used in field/method options, and in fact not actual dependencies to make the GRPC call.

Our current workaround is to [fork](https://github.com/hoveychen/grpcui) the underlying project `jhump/protoreflect`, and provide an opt-out option to ignore failure to reflect these lib.

Looking forward to a better solution.