Support Helidon Reflection

[Nana-EC]

Story Form

As a block node engineer
I want to enable the Helidon reflection feature
So that gRPC list calls are supported

Technical Notes

It's common for users to do a gRPC list when they hit a server.

grpcurl -plaintext "localhost:8080" list

Currently that does not work for the BN due to Helidon disabling it by default.
That results in the following error

Failed to list services: rpc error: code = Unknown desc = malformed header: missing HTTP content-type

We should explore

1. If we should support it based on the default concerns
2. How to enable it based on Helidon docs
3. If we should make it configureable so that operators can make their choice

[Nana-EC]

@georgi-l95 noted
we either need to allow usage of GrpcReflectionFeature and extend the webserver by adding something like

.addFeature(GrpcReflectionFeature.builder().enabled(true).build()

or maybe extend the helidon plugin to support this, so we don't introduce dependencies on our side and let pbj helidon plugin handle all this.

[AlfredoG87]

see reference issue. it was included on version v4.2.2 which is the latest and we already support on the BN codebase.
helidon-io/helidon#10014

See this test as an example of how to enable:

https://github.com/helidon-io/helidon/blob/main/webserver/tests/grpc/src/test/java/io/helidon/webserver/tests/grpc/ReflectionServiceTest.java#L62

[jsync-swirlds]

Just a note. We have generally avoided enabling any feature based on reflection due to the cost and security concerns; it also tends to have trouble with cross-module interactions. Just something to consider before enabling this.