refactor the use of plain string order types

src/pages/checkout/components/CheckoutButton.tsx

@@ -6,10 +6,11 @@ import { useNavigate, useParams } from "react-router-dom";
 import { useAppSelector } from "redux/hooks";
 import styles from "../../address/address.module.css";
 import useOrder from "../hooks/useOrder";
+import { OrderType } from "pages/checkout/hooks/types.ts";
 
 export default function CheckoutButton({ form }: { form: FormInstance }) {
   const { t } = useTranslation();
-  const { orderType } = useAppSelector(selectCart)
+  const { orderType } = useAppSelector(selectCart);
   const navigate = useNavigate();
   const { handleCreateOrder } = useOrder();
   const { id } = useParams();
@@ -28,7 +29,7 @@ export default function CheckoutButton({ form }: { form: FormInstance }) {
   }, [handleCreateOrder, form]);
 
   const shouldShowSplitBill = useMemo(
-    () => orderType === "dine-in",
+    () => orderType === OrderType.DineIn,
     [orderType],
   );