Fixed RenderFlex overflow in RouteObserver Example (#170980)

Fixed RenderOverflow in RouteObserver Example:
https://api.flutter.dev/flutter/widgets/RouteObserver-class.html

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This PR is about solving render overflow issue in Route Observer Example
in Live Website. I've wrapped the body with a Scrollable View to solve
this issue

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![image](https://github.com/user-attachments/assets/c8fa78e7-62ca-4bd1-9798-588c636cd61a)
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---------

Co-authored-by: Victor Sanni <victorsanniay@gmail.com>

examples/api/lib/widgets/routes/route_observer.0.dart

@@ -63,37 +63,39 @@ class _RouteObserverExampleState extends State<RouteObserverExample>
   @override
   Widget build(BuildContext context) {
     return Scaffold(
-      body: Center(
-        child: Column(
-          mainAxisSize: MainAxisSize.min,
-          children: <Widget>[
-            Text(
-              'RouteObserver log:',
-              style: Theme.of(context).textTheme.headlineSmall,
-            ),
-            ConstrainedBox(
-              constraints: const BoxConstraints(maxHeight: 300.0),
-              child: ListView.builder(
-                itemCount: log.length,
-                itemBuilder: (BuildContext context, int index) {
-                  if (log.isEmpty) {
-                    return const SizedBox.shrink();
-                  }
-                  return Text(log[index], textAlign: TextAlign.center);
-                },
+      body: SingleChildScrollView(
+        child: Center(
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            children: <Widget>[
+              Text(
+                'RouteObserver log:',
+                style: Theme.of(context).textTheme.headlineSmall,
               ),
-            ),
-            OutlinedButton(
-              onPressed: () {
-                Navigator.of(context).push<void>(
-                  MaterialPageRoute<void>(
-                    builder: (BuildContext context) => const NextPage(),
-                  ),
-                );
-              },
-              child: const Text('Go to next page'),
-            ),
-          ],
+              ConstrainedBox(
+                constraints: const BoxConstraints(maxHeight: 300.0),
+                child: ListView.builder(
+                  itemCount: log.length,
+                  itemBuilder: (BuildContext context, int index) {
+                    if (log.isEmpty) {
+                      return const SizedBox.shrink();
+                    }
+                    return Text(log[index], textAlign: TextAlign.center);
+                  },
+                ),
+              ),
+              OutlinedButton(
+                onPressed: () {
+                  Navigator.of(context).push<void>(
+                    MaterialPageRoute<void>(
+                      builder: (BuildContext context) => const NextPage(),
+                    ),
+                  );
+                },
+                child: const Text('Go to next page'),
+              ),
+            ],
+          ),
         ),
       ),
     );

examples/api/test/widgets/routes/route_observer.0_test.dart

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:flutter/rendering.dart';
 import 'package:flutter_api_samples/widgets/routes/route_observer.0.dart'
     as example;
 import 'package:flutter_test/flutter_test.dart';
@@ -38,5 +39,24 @@ void main() {
     // Check the RouteObserver logs after the route is popped again.
     expect(find.text('didPush'), findsOneWidget);
     expect(find.text('didPopNext'), findsNWidgets(2));
+
+    // Check if any overflow or layout exceptions occurred.
+    expect(tester.takeException(), isNull);
   });
+
+  testWidgets(
+    'RouteObserver example renders without overflow on small screens',
+    (WidgetTester tester) async {
+      // Set the screen size to a smaller value.
+      tester.view.physicalSize = const Size(200, 200);
+      addTearDown(tester.view.reset);
+
+      // Build the RouteObserver example widget.
+      await tester.pumpWidget(const example.RouteObserverApp());
+      await tester.pumpAndSettle();
+
+      // Verify there are no layout exceptions.
+      expect(tester.takeException(), isNull);
+    },
+  );
 }