small fix, don't worry about it

lifetimer/lib/features/calendar/presentation/calendar_screen.dart

@@ -522,6 +522,7 @@ Future<void> _showAddCalendarEntrySheet(
                 ],
                 ElevatedButton(
                   onPressed: () async {
+                    final navigator = Navigator.of(sheetContext);
                     await ref
                         .read(calendarControllerProvider.notifier)
                         .addEntry(
@@ -529,8 +530,8 @@ Future<void> _showAddCalendarEntrySheet(
                           note: noteController.text,
                           goalId: selectedGoalId,
                         );
-                    if (Navigator.of(sheetContext).canPop()) {
-                      Navigator.of(sheetContext).pop();
+                    if (navigator.canPop()) {
+                      navigator.pop();
                     }
                   },
                   child: const Text('Save to calendar'),