fix: Avoid failing on public dav URLs

Signed-off-by: Julius Knorr <jus@bitgrid.net>

lib/Service/AssignmentService.php

@@ -88,8 +88,6 @@ class AssignmentService {
 		$this->changeHelper = $changeHelper;
 		$this->activityManager = $activityManager;
 		$this->eventDispatcher = $eventDispatcher;
-
-		$this->assignmentServiceValidator->check(compact('userId'));
 		$this->currentUser = $userId;
 	}
 

lib/Service/CardService.php

@@ -38,7 +38,7 @@ use Psr\Log\LoggerInterface;
 
 class CardService {
 
-	private string $currentUser;
+	private ?string $currentUser;
 
 	public function __construct(
 		private CardMapper $cardMapper,