fix success add item order

lib/domain/order/entities/order_entity.dart

@@ -178,6 +178,9 @@ class Order with _$Order {
         totalAmount: products
             .map((e) => e.product.price.toInt() * e.quantity)
             .reduce((value, element) => value + element),
+            subtotal: products
+            .map((e) => e.product.price.toInt() * e.quantity)
+            .reduce((value, element) => value + element),
       );
 
   List<OrderItem> get orderItemNotCancelled =>