refactor calculation code

- implement fee
- centralize the code

src/pages/checkout/hooks/useOrder.ts

@@ -2,8 +2,8 @@ import { message } from "antd";
 import {
   clearCart,
   selectCart,
-  selectCartTotalWithLoyaltyDiscount,
-  selectHighestPricedLoyaltyItem,
+  selectGrandTotal,
+  selectHighestPricedLoyaltyItem
 } from "features/order/orderSlice";
 import { useCallback } from "react";
 import { useTranslation } from "react-i18next";
@@ -37,7 +37,7 @@ export default function useOrder() {
   const highestLoyaltyItem = useAppSelector(selectHighestPricedLoyaltyItem);
   const { useLoyaltyPoints } = useAppSelector(selectCart);
 
-  const orderPrice = useAppSelector(selectCartTotalWithLoyaltyDiscount);
+  const orderPrice = useAppSelector(selectGrandTotal);
 
   const [createOrder] = useCreateOrderMutation();