Turn on --web-resources-cdn by default (#123425)

packages/flutter_tools/lib/src/runner/flutter_command.dart

@@ -669,9 +669,9 @@ abstract class FlutterCommand extends Command<void> {
   }
 
   void usesWebResourcesCdnFlag() {
-    // TODO(hterkelsen): Default to true once we have a smoke test.
     argParser.addFlag(
       FlutterOptions.kWebResourcesCdnFlag,
+      defaultsTo: true,
       help: 'Use Web static resources hosted on a CDN.',
     );
   }