Changes to Handles callbacks from SheerID's Zero Knowledge Proof technology

added the optional property tryAgainUrl to the response with the 429 status

added the new inCountryVerification enum value to the currentStep response property for the response status 429

removed the media type text/html for the response with the status 200

added the media type application/json for the response with the status 200

added the optional property metadata to the response with the 400 status