gRPC method call doesn't respond when status code is not OK

[fgarciacode]

Describe the bug
I have a custom gRPC service, the response of its methods sometimes return status codes different to "0 OK" (NotFound, AlreadyExists, PermissionDenied, Unauthenticated). Zilla doesn't respond when the status code of my gRPC is different to "0 OK".

To Reproduce
Steps to reproduce the behavior:

1. Checkout https://github.com/fgarcia-code/examples/tree/main/zilla/echo and start.
2. Use Postman to call the gRPC EchoStatus service with status "OK":
   
3. Call with status "Not Found":
   
4. Review UI for Apache Kafka, the service publish in echo-requests, but not in echo-responses.
   

Expected behavior
I think that Zilla should responds in the same way with the status code.

I don't know if I'm doing something wrong.

[jfallows]

@fgarcia-code thank you, we'll look into this a post an update.

[jfallows]

@fgarcia-code we are testing a fix, please see #519.