How to change the navigatorKey to allow the user to change the page ?

I'm using the package "Awesome Notifications" wich works great :
https://pub.dev/packages/awesome_notifications/versions/0.9.3+1

I'm trying to use a listener in order to load a specific page if the user clicks on the notification :

class NotificationController {
  /// Use this method to detect when the user taps on a notification or action button
  @pragma("vm:entry-point")
  static Future <void> onActionReceivedMethod(ReceivedAction receivedAction) async {
    // Navigate into pages, avoiding to open the notification details page over another details page already opened
    MyApp.navigatorKey.currentState?.pushNamedAndRemoveUntil('/notification-page',
            (route) => (route.settings.name != '/notification-page') || route.isFirst,
        arguments: receivedAction);
  }
}

And in this exemple the author is using MyApp.navigatorKey assigned here :

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      navigatorKey: navigatorKey,
      home: HomePage(),
    );
  }
}

But i don't know in flutterflow how to access class MyApp extends StatelessWidget or change the navigatorKey ?