Get guest code

Get guest code data for reservations with future check-out times, by reservation ID. Note: The main guest codes are codes with "purpose" set to "GUEST". Codes with "purpose" set to "GUEST_BACKUP" are codes to share with guests in case the "GUEST" code has errors, starting from the check-in day. "GUEST_BACKUP" codes are a dynamic pool of codes associated with reservations on check-in day. When fetching a "GUEST_BACKUP" code before the check-in day, the code is not guaranteed to stay the same until the check-in day.