enh: validate user id before saving group

backend/open_webui/routers/groups.py

@@ -2,6 +2,8 @@ import os
 from pathlib import Path
 from typing import Optional
 
+
+from open_webui.models.users import Users
 from open_webui.models.groups import (
     Groups,
     GroupForm,
@@ -80,6 +82,9 @@ async def update_group_by_id(
     id: str, form_data: GroupUpdateForm, user=Depends(get_admin_user)
 ):
     try:
+        if form_data.user_ids:
+            form_data.user_ids = Users.get_valid_user_ids(form_data.user_ids)
+
         group = Groups.update_group_by_id(id, form_data)
         if group:
             return group