[BUG][erlang-server] faulty content_types_provided

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• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
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Description

When schema provide content type for response it doesn't effect the generated code:

          "201" : {
            "content" : {
              "application/3gppHal+json" : {
                "schema" : {
                  "$ref" : "#/components/schemas/UEAuthenticationCtx"
                }
              }

generates:

content_types_provided(Req, State) ->
    {[
        {<<"application/json">>, handle_request_json}
    ], Req, State}.

expected:

content_types_provided(Req, State) ->
    {[
        {<<"application/3gppHal+json">>, handle_request_json},
        {<<"application/json">>, handle_request_json}
    ], Req, State}.

openapi-generator version

openapi-generator-cli 5.2.0-SNAPSHOT
commit : 24836cd

OpenAPI declaration file content or url

https://www.3gpp.org/ftp/Specs/archive/OpenAPI/Rel-15/TS29510_Nnrf_NFManagement.yaml

Generation Details

Steps to reproduce

Related issues/PRs

Suggest a fix

Start with the Erlang server generated from the linked TS29510_Nnrf_NFManagement.yaml declaration and inspect its content_types_provided output. Compare the generated media types with the response content entries, including application/3gppHal+json; done when both that type and application/json are emitted with the expected handler.