Fix keyboard cover SearchAnchor list results (#165382)

Fix https://github.com/flutter/flutter/issues/159261

We can leverage `MediaQuery.viewInsets` to handle this case. Once the
keyboard prompts and covers the SearchAnchor suggestion list, it will
need a bottom padding equivalent to
`MediaQuery.viewInsetsOf(context).bottom` so that it's possible to view
the whole list.

| before | after |
| --------------- | --------------- |
<video
src="https://github.com/user-attachments/assets/38a1c343-e3eb-4e42-a523-eef9fb4d5dbc"/>
| <video
src="https://github.com/user-attachments/assets/533aeca4-08c1-494f-9d47-3775ed9157d0"/>


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we expect every widget to implement].
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above.
- [x] I updated/added relevant documentation (doc comments with `///`).
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[test-exempt].
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---------

Signed-off-by: huycozy <huy@nevercode.io>

packages/flutter/lib/src/material/search_anchor.dart

@@ -1146,6 +1146,9 @@ class _ViewContentState extends State<_ViewContent> {
                                       context: context,
                                       removeTop: true,
                                       child: ListView(
+                                        padding: EdgeInsets.only(
+                                          bottom: MediaQuery.viewInsetsOf(context).bottom,
+                                        ),
                                         shrinkWrap: effectiveShrinkWrap,
                                         children: result.toList(),
                                       ),

packages/flutter/test/material/search_anchor_test.dart

@@ -4058,6 +4058,47 @@ void main() {
     await tester.pump();
     expect(searchViewState, 'Closed');
   });
+
+  testWidgets(
+    'The last element of the suggestion list should be visible when scrolling to the end of list',
+    (WidgetTester tester) async {
+      await tester.pumpWidget(
+        MaterialApp(
+          home: SearchAnchor.bar(
+            suggestionsBuilder: (BuildContext context, SearchController controller) {
+              return List<Widget>.generate(30, (int index) {
+                return ListTile(
+                  titleAlignment: ListTileTitleAlignment.center,
+                  title: Text('Item $index'),
+                );
+              });
+            },
+          ),
+        ),
+      );
+
+      // Open search view.
+      await tester.tap(find.byIcon(Icons.search));
+      await tester.pumpAndSettle();
+      const double fakeKeyboardHeight = 500.0;
+      final double physicalBottomPadding = fakeKeyboardHeight * tester.view.devicePixelRatio;
+
+      // Simulate the keyboard opening resizing the view.
+      tester.view.viewInsets = FakeViewPadding(bottom: physicalBottomPadding);
+      addTearDown(tester.view.reset);
+
+      // Scroll down to the end of the list.
+      expect(find.byType(ListView), findsOne);
+      await tester.fling(find.byType(ListView), const Offset(0, -5000), 5000);
+      await tester.pumpAndSettle();
+
+      // The last item should not be hidden by the keyboard.
+      final double lastItemBottom = tester.getRect(find.text('Item 29')).bottom;
+      final double fakeKeyboardTop =
+          tester.getSize(find.byType(MaterialApp)).height - fakeKeyboardHeight;
+      expect(lastItemBottom, lessThanOrEqualTo(fakeKeyboardTop));
+    },
+  );
 }
 
 Future<void> checkSearchBarDefaults(