Small improvements

app/Domains/Event/Controllers/SignupController.php

@@ -97,7 +97,8 @@ class SignupController extends CommonController {
         );
 
         $signupRequest = new SignUpRequest(
-            $event,$registrationData['userId'],
+            $event,
+            $registrationData['userId'] ?? null,
             $registrationData['vorname'],
             $registrationData['nachname'],
             $registrationData['pfadiname'],