fix: Django 1:N 모델에 직접 설정하려 한 에러 수정

Author: MU-Software

app/participant_portal_api/models.py

@@ -73,9 +73,6 @@ def apply_modification(self, save: bool = False) -> models.Model:
 
                     if save:
                         sub_instance.save()
-
-                if not save:
-                    setattr(self.instance, field, sub_instances)
             elif isinstance(value, dict):
                 # One to One case
                 if not (sub_instance := getattr(self.instance, field, None)):