VSN-2252/ Update absence status flow and allow user to cancel absences
The changes included in this MR are as follows :
- Absences created from mobile now default to "Validé" (Processed) instead of "En attente" (Unprocessed)
- Reduced visible statuses to only "Validé" and "Annulé"
- Users can now cancel their own absences directly from the app
- Cancelled absences are locked: edit, delete, and cancel actions are disabled with padlock icon