Resolve VSN-2064 "Feature/ simplify employee management and add cancel action"
feat(user-absence): simplify employee management and add cancel action
- Replace employee selection with auto-populated logged-in user
- Limit form status options to 'In Progress' / 'Not Processed'
- Add 'Cancel' action button with confirmation dialog
- Unify validation/cancellation dialogs with ACTION_CONFIG
- Update 'by' field with user who validates/cancels
- Refactor absence-utils with reusable helpers
- Fix duplicate API call during save operation Closes VSN-2064