fix(FocusScope): Example fix (#98668)

examples/api/lib/widgets/focus_scope/focus.2.dart

@@ -43,10 +43,10 @@ class _MyStatefulWidgetState extends State<MyStatefulWidget> {
 
   @override
   void dispose() {
-    super.dispose();
     for (final FocusNode node in childFocusNodes) {
       node.dispose();
     }
+    super.dispose();
   }
 
   void _addChild() {

examples/api/lib/widgets/focus_scope/focus_scope.0.dart

@@ -80,9 +80,9 @@ class _MyStatefulWidgetState extends State<MyStatefulWidget> {
 
   @override
   void dispose() {
-    super.dispose();
     backdropNode.dispose();
     foregroundNode.dispose();
+    super.dispose();
   }
 
   Widget _buildStack(BuildContext context, BoxConstraints constraints) {