Fix Telegram notifications

src/backend/users/serializers.py

@@ -257,7 +257,7 @@ def update(self, instance: User, validated_data: Dict[str, Any]) -> User:
             User: Updated instance
         """
         if hasattr(instance, "telegram_chat"):
-            Telegram().logout_after_password_change_message(user.telegram_chat)
+            Telegram().logout_after_password_change_message(instance.telegram_chat)
         return User.objects.update_password(instance, validated_data.get("password"))