feat: pre-flight check of agency bookings

addresses #869bqxr4q

src/Form/Model/BookingDto.php

@@ -380,7 +380,7 @@ class BookingDto
 
         foreach ($this->participants as $participant) {
             // Temporary cleanup for older serialized participants restored from session.
-            $participant->normalizeBodyDimensions();
+            $participant->normalizeLoadedData();
         }
 
         // Old sessions (before c373a989) still carry a full Travel object;