migrated custom timetable events to Marianum-Connect and refactored push notification handling

lib/view/pages/timetable/widgets/timetable_calendar_view.dart

@@ -79,6 +79,7 @@ class TimetableCalendarViewState extends State<TimetableCalendarView> {
       lessons: state.getAllKnownLessons().toList(),
       customEvents: widget.customEvents,
       subjects: state.subjects?.result ?? const [],
+      holidays: state.schoolHolidays?.result ?? const [],
       settings: timetableSettings,
       now: DateTime.now(),
     ).build();