Underlying Content is not shown when dialog is open on top of the page using go_router

Question

I'm facing this issue as you can see in the Screen Shot,Underlying Content is not shown when dialog is open on top of the page using go_router. I used the following approach to show the overlay or dialog using go_router package.

class DialogScreen<T> extends Page<T> {
  final Offset? anchorPoint;
  final Color? barrierColor;
  final bool barrierDismissible;
  final String? barrierLabel;
  final bool useSafeArea;
  final CapturedThemes? themes;
  final WidgetBuilder builder;

  const DialogScreen({
    required this.builder,
    this.anchorPoint,
    this.barrierColor = Colors.black54,
    this.barrierDismissible = true,
    this.barrierLabel,
    this.useSafeArea = true,
    this.themes,
    super.key,
    super.name,
    super.arguments,
    super.restorationId,
  });

  @override
  Route<T> createRoute(BuildContext context) => DialogRoute<T>(
    context: context,
    settings: this,
    builder: (context) => Dialog(
      backgroundColor: Colors.transparent,
      
      child: builder(context),

    ),
    anchorPoint: anchorPoint,
    barrierColor: barrierColor,
    barrierDismissible: barrierDismissible,
    barrierLabel: barrierLabel,
    useSafeArea: useSafeArea,
    themes: themes,

  );
}

Here is my web_routes.dart file:

class WebRoutes {
  static final GoRouter goRouter = GoRouter(
    navigatorKey: NavigationService.navigatorKey,
    initialLocation: kIsWeb ? '/' : "/login",

    //'/login',
    debugLogDiagnostics: true,
    routes: [
      


            GoRoute(
        name: "testDialog",
        path: '/testDialog',
        pageBuilder:
            (BuildContext context, GoRouterState state) {
          return
            DialogScreen(
            barrierColor: Colors.transparent,
              barrierDismissible: true,
              builder: (context) =>
              const TestScreen());
        },
      ),}

please note: I used this approach as I want to show the url on the address bar, other genneral way is working fine.