refac/fix: ldap issue

backend/open_webui/routers/auths.py

@@ -234,7 +234,7 @@ async def ldap_auth(request: Request, response: Response, form_data: LdapForm):
             ],
         )
 
-        if not search_success:
+        if not search_success or not connection_app.entries:
             raise HTTPException(400, detail="User not found in the LDAP server")
 
         entry = connection_app.entries[0]