Update widget_test.dart

LayoutBuilder migration: LayoutBuilders no longer do double layout (currently the fix is behind a temporary flag).

Related flutter/flutter PR:  flutter/flutter#147856

test/widget_test.dart

@@ -42,6 +42,8 @@ Future<ByteData> fetchFont() async {
 Future<void> main() async {
   final fontLoader = FontLoader('Roboto')..addFont(fetchFont());
   await fontLoader.load();
+  setUp(() { LayoutBuilder.applyDoubleRebuildFix = true; });
+  tearDown(() { LayoutBuilder.applyDoubleRebuildFix = false; });
 
   testWidgets('can optionally delay close with a Duration', (tester) async {
     await tester.pumpWidget(
@@ -1365,7 +1367,7 @@ Future<void> main() async {
     expect(find.text('1'), findsOneWidget);
     expect(find.text('1 1'), findsOneWidget);
     expect(entryBuild.calls,
-        const [EntryBuildSpyCall(0, 1), EntryBuildSpyCall(1, 1)]);
+        const [EntryBuildSpyCall(1, 1)]);
   });
 
   testWidgets('layout builder between portal and entry on first build',