Changes to Get list of approval methods available for request

removed the media type application/json for the response with the status 404

removed the media type application/json for the response with the status 500

removed the media type text/html for the response with the status 404

removed the media type text/html for the response with the status 500

removed the media type text/json for the response with the status 404

removed the media type text/json for the response with the status 500