Fix reservation user not being saved by mistake

api/graphql/types/reservation/serializers/create_serializers.py

@@ -165,7 +165,7 @@ def validate(self, data: dict[str, Any], prefill_from_profile: bool = True) -> d
  data["buffer_time_before"], data["buffer_time_after"] = self._calculate_buffers(begin, end, reservation_units)
 
  request_user: AnyUser = self.context["request"].user
- data["user"] = request_user if request_user.is_anonymous else None
+ data["user"] = None if request_user.is_anonymous else request_user
  data["reservee_used_ad_login"] = (
  False if request_user.is_anonymous else getattr(request_user.id_token, "is_ad_login", False)
  )