Allow setting parts for http trigger response when function returns a json

[pragnagopa]

cc @mhoeger

Following code allows setting StatusCode, Headers, Query etc on http response only if body is set.

azure-functions-host/src/WebJobs.Script/Binding/Http/HttpBinding.cs

Lines 118 to 142 in 680243f

	if (responseObject.TryGetValue(RpcWorkerConstants.RpcHttpBody, out bodyValue, ignoreCase: true))
	{
	// the response content becomes the specified body value
	content = bodyValue;
	if (responseObject.TryGetValue(RpcWorkerConstants.RpcHttpHeaders, out IDictionary<string, object> headersValue, ignoreCase: true))
	{
	headers = headersValue;
	}
	if (TryParseStatusCode(responseObject, out int? responseStatusCode))
	{
	statusCode = responseStatusCode.Value;
	}
	if (responseObject.TryGetValue<bool>(RpcWorkerConstants.RpcHttpEnableContentNegotiation, out bool enableContentNegotiationValue, ignoreCase: true))
	{
	enableContentNegotiation = enableContentNegotiationValue;
	}
	if (responseObject.TryGetValue(RpcWorkerConstants.RpcHttpCookies, out List<Tuple<string, string, CookieOptions>> cookiesValue, ignoreCase: true))
	{
	cookies = cookiesValue;
	}
	}

This code effects out-of-proc and .csx functions. Fixing it would be breaking change. Have to fix this as part of next major release.

[brettsam]

@pragnagopa -- I assume this is something we still want to get in for v4?