[http-server-csharp] No interfaces and controllers generated when ops are wrapped inside a namespace

[ArcturusZhang]

I saw this issue when I am trying to generate the petstore: https://github.com/microsoft/typespec/tree/main/packages/samples/specs/petstore
Because of this issue, I removed everything related with templated models (including models and operations), and only models are generated.

FYI, changing namespace to interface would do the trick. But this does not really make sense, namespace should work just fine.

[markcowl]

I think this is fixed by: #5140