Changes to Open a session and mint a data-plane grant

added the optional property agent/error to the response with the 201 status

the success response property const value false was added for the status 400

the success response property const value false was added for the status 401

the success response property const value false was added for the status 403

the success response property const value false was added for the status 404

the success response property const value false was added for the status 429

the success response property const value false was added for the status 500

the success response property const value false was added for the status 503

endpoint added