DateTimePicker: simplify onTap handler for close icon

Remove the redundant call to _done() in the close icon's onTap handler
and simplify the callback to a single-expression setState. The change
keeps behavior focused on hiding the time view (_showTime = false) and
avoids invoking _done() on close, which aligns with the intended UI flow
signaled by the task notification that the Flutter app relaunch
completed successfully.

apps/flutter/lib/src/widgets/date_time_picker.dart

@@ -184,7 +184,7 @@ class _DateTimePickerState extends State<DateTimePicker> {
                       ),
                       const Spacer(),
                       GestureDetector(
-                        onTap: () { setState(() => _showTime = false); _done(); },
+                        onTap: () => setState(() => _showTime = false),
                         child: Icon(Icons.close, size: 18, color: (isDark ? AppTheme.textSecondaryDark : AppTheme.textSecondaryLight).withAlpha(160)),
                       ),
                     ],