Changes to Get User Contacts

added the new registered enum value to the items/status response property for the response status 200

removed the existing_user enum value from the items/status response property for the response status 200

removed the invitation_accepted enum value from the items/status response property for the response status 200

removed the optional property items/last_name from the response with the 200 status

removed the optional property items/name from the response with the 200 status

removed the optional property items/user_ext_id from the response with the 200 status

added the optional property items/user to the response with the 200 status

endpoint added