Fix: Return single order object ved cancel_order (ikke list)

BUG FIX:
- execute_query returnerer list, men TModuleOrder(**updated) forventede dict
- TypeError: argument after ** must be a mapping, not list
- Changed til updated[0] for at få første row
- Dette er den SIDSTE execute_query/execute_query_single bug i order_service.py

ERROR: TModuleOrder() argument after ** must be a mapping, not list
  → return TModuleOrder(**updated)
  → updated er list, skal være dict

app/timetracking/backend/order_service.py

@@ -448,7 +448,7 @@ class OrderService:
                 "SELECT * FROM tmodule_orders WHERE id = %s",
                 (order_id,))
             
-            return TModuleOrder(**updated)
+            return TModuleOrder(**updated[0])
         
         except HTTPException:
             raise