Specify a per-method / per-error code retry policy on the grpc client.

### Problem

You can specify a per-method / per-error code retry policy on the grpc client.

- https://github.com/grpc/proposal/blob/master/A6-client-retries.md#integration-with-service-config
- https://github.com/grpc/grpc-java/blob/master/examples/src/main/resources/io/grpc/examples/retrying/retrying_service_config.json
- https://github.com/grpc/grpc-java/blob/master/examples/src/main/java/io/grpc/examples/retrying/RetryingHelloWorldClient.java

In there, we could specify any idempotent methods. If we do that then the grpc clients SDKs should respect the retries and maybe we'll see fewer problems with people having to implement custom retry logic (in some cases).

We should provide this config in our SDKs and then they will know how to handle retries. I suspect that GOAWAY error will then disappear

### Solution

- [ ] Research proposed solution
- [ ] Test to see it decreases the rate at which the `UNAVAILABLE` error is returned

### Alternatives

_No response_