Using custom CADL operation template and getting unexpected response in DPG code

[catalinaperalta]

Describe the issue or request
The service team is using the following operation template:

@doc("Long running RPC operation template")
op LongRunningRpcOperation<
    TParams extends object,
    TResponse extends object
  > is RpcOperation<
    TParams,
    Foundations.AcceptedResponse<TResponse &
      Foundations.LongRunningStatusLocation>
  >;

This is causing the operation signature to come out as the operation returning an AcceptedResponse instead of the TResponse.

Current output:

public virtual async Task<Operation<AcceptedResponse>> InferOncologyPhenotypingAsync(WaitUntil waitUntil, OncoPhenotypeRequest oncoPhenotypeRequest, CancellationToken cancellationToken = default)

Describe your ideas for solutions

Expected output:

public virtual async Task<Operation<OncoPhenotypeResponse>> InferOncologyPhenotypingAsync(WaitUntil waitUntil, OncoPhenotypeRequest oncoPhenotypeRequest, CancellationToken cancellationToken = default)

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[catalinaperalta]

cc @m-nash