remove leftover of avatar generator (#1366)

api/models/robot.py

@@ -88,25 +88,5 @@ def create_user_robot(sender, instance, created, **kwargs):
     def save_user_robot(sender, instance, **kwargs):
         instance.robot.save()
 
-    @receiver(pre_delete, sender=User)
-    def del_avatar_from_disk(sender, instance, **kwargs):
-        try:
-            avatar_file = Path(
-                settings.AVATAR_ROOT + instance.robot.avatar.url.split("/")[-1]
-            )
-            avatar_file.unlink()
-        except Exception:
-            pass
-
     def __str__(self):
         return self.user.username
-
-    # to display avatars in admin panel
-    def get_avatar(self):
-        if not self.avatar:
-            return settings.STATIC_ROOT + "unknown_avatar.png"
-        return self.avatar.url
-
-    # method to create a fake table field in read only mode
-    def avatar_tag(self):
-        return mark_safe('<img src="%s" width="50" height="50" />' % self.get_avatar())