[openapi to tsp] Fix accept header logic

[catalinaperalta]

Given the following swagger definition:

        "produces": [
          "application/vnd.microsoft.appconfig.kv+json",
          "application/problem+json"
        ],

The converter outputs the following typespec code where all of the supported content types are bundled into 1 string:

accept: "application/vnd.microsoft.appconfig.kv+json, application/problem+json";

The correct code should represent each content type individually:

accept: "application/vnd.microsoft.appconfig.kv+json" | "application/problem+json";

cc @joheredi

[pshao25]

@catalinaperalta could you show me the full swagger so that I could know which template we should use for this operation. I assume it might be ResourceRead, which seems lack of ability to override the content type. So I'm going to ask TSP team. Before that I need to know the full story.

[catalinaperalta]

This spec was converted to typespec a few months ago so you'll have to look at an older version of the swagger, linking it here: https://github.com/Azure/azure-rest-api-specs/blob/c1af3ab8e803da2f40fc90217a6d023bc13b677f/specification/appconfiguration/data-plane/Microsoft.AppConfiguration/stable/2023-11-01/appconfiguration.json

IIRC you'll be able to see that there are several operations with multiple produces statements it wasnt just a 1 time occurrence in the converted code.