VSN-2436/ feat(absence): add leaveType and otherLeaveDescription fields to DriverAbsence entity

Added leaveType and otherLeaveDescription fields to the DriverAbsence entity to persist leave request details created from the mobile app.

Previously, mobile leave requests were saved with absenceType=OTHER and leaveType was only resolved at query time via an RH system lookup which could fail silently and return null. These two fields are now stored directly on the entity at creation time, ensuring the leave type is always available regardless of RH enrichment.