I'd like to return `['webpush']` in the `via()` method instead of `WebPushChannel::class`. I based on https://medium.com/@sirajul.anik/laravel-notifications-part-2-creating-a-custom-notification-channel-6b0eb0d81294 and tried to register it in the `AppServiceProvider.php` with: ```php Notification::extend('webpush', function ($app) { return new WebPushChannel(); }); ``` but `WebPushChannel()` constructor needs additional parameters and this method fails.