Skip push notifications for banned users

See https://www.woltlab.com/community/thread/314776/

Author: dtdesign

wcfsetup/install/files/lib/system/background/job/ServiceWorkerDeliveryBackgroundJob.class.php

@@ -88,7 +88,12 @@ private function sendNotification(int $serviceWorkerID, int $notificationID): vo
         }
         $user = WCF::getUser();
         try {
-            SessionHandler::getInstance()->changeUser(new User($notification->userID), true);
+            $targetUser = new User($notification->userID);
+            if ($targetUser->banned) {
+                return;
+            }
+
+            SessionHandler::getInstance()->changeUser($targetUser, true);
             $processedNotifications = UserNotificationHandler::getInstance()->processNotifications([$notification]);
             if ($processedNotifications['count'] == 0) {
                 return;