fix: report an unresolvable hotel instead of failing on it

src/Model/DestinationDto.php

@@ -3,6 +3,7 @@
 namespace App\Model;
 
 use App\Entity\Destination;
+use App\Validator\Constraints as AppAssert;
 use Symfony\Component\Validator\Constraints as Assert;
 
 class DestinationDto
@@ -36,6 +37,7 @@ class DestinationDto
     private ?\DateTimeImmutable $dateTo = null;
 
     #[Assert\NotBlank(message: 'Bitte angeben')]
+    #[AppAssert\ResolvableHotel]
     private ?string $hotelBusProId = null;
 
     private ?string $costUnit = null;