Merge pull request #51079 from nextcloud/fix/do-not-remind

fix(files_reminders): Do not attempt to send reminders after a user has left a share

apps/files_reminders/lib/Notification/Notifier.php

@@ -14,6 +14,7 @@
 use OCP\Files\IRootFolder;
 use OCP\IURLGenerator;
 use OCP\L10N\IFactory;
+use OCP\Notification\AlreadyProcessedException;
 use OCP\Notification\IAction;
 use OCP\Notification\INotification;
 use OCP\Notification\INotifier;
@@ -51,8 +52,8 @@ public function prepare(INotification $notification, string $languageCode): INot
 				$fileId = $params['fileId'];
 
 				$node = $this->root->getUserFolder($notification->getUser())->getFirstNodeById($fileId);
-				if (!$node) {
-					throw new UnknownNotificationException();
+				if ($node === null) {
+					throw new AlreadyProcessedException();
 				}
 
 				$path = rtrim($node->getPath(), '/');