fix: corrupted logic of model transformer

src/Form/DataTransformer/RoomSelectionToIdTransformer.php

@@ -59,12 +59,8 @@ class RoomSelectionToIdTransformer implements DataTransformerInterface
             return null;
         }
 
-        if (is_int($value)) {
-            return $value;
-        }
-
-        if (is_string($value) && ctype_digit($value)) {
-            return (int) $value;
+        if ($value instanceof RoomSelectionDto) {
+            return $value->id;
         }
 
         throw new TransformationFailedException(sprintf(