[web] Re-enable text field test now that fix has landed in engine (#140678)

Re-enables skipped flaky test now that the underlying cause of flakiness (GPU memory leak) has been fixed in the engine and the fix has rolled into the framework.

The fix is here: https://github.com/flutter/engine/pull/49336

Fixes https://github.com/flutter/flutter/issues/137669

packages/flutter/test/cupertino/text_field_test.dart

@@ -8390,13 +8390,10 @@ void main() {
     final EditableText editableText = tester.firstWidget(find.byType(EditableText));
     expect(editableText.clipBehavior, Clip.none);
 
-    // TODO(harryterkelsen): see https://github.com/flutter/flutter/issues/137669
-    if (!kIsWeb || !isCanvasKit) {
     await expectLater(
       find.byKey(const ValueKey<int>(1)),
       matchesGoldenFile('overflow_clipbehavior_none.cupertino.0.png'),
     );
-    }
   });
 
   testWidgets('can shift + tap to select with a keyboard (Apple platforms)', (WidgetTester tester) async {