Add default HTTP routes for non-annotated methods

I have the following program: https://github.com/anhnmt/gprc-dynamic-proto/blob/main/cmd/service/main.go

I have successfully connected grpc and restapi, can I call the api like the following?

```bash
curl --header "Content-Type: application/json" \
    --data '{}' \
    http://localhost:8080/user.v1.UserService/List
```
 I tried and the result was: Not Found