add prompt confirmation and update carton

lib/domain/entities/rate.dart

@@ -44,6 +44,12 @@ class Rate {
     };
   }
 
+  bool isChangedForEdit(Rate rate) {
+    return rate.freeDeliveryWeight != this.freeDeliveryWeight ||
+        rate.deliveryFee != this.deliveryFee ||
+        rate.volumetricRatio != this.volumetricRatio;
+  }
+
   @override
   String toString() {
     return 'Rate{deliveryFee:$deliveryFee,freeDeliveryWeight:$freeDeliveryWeight,volumetricRatio:$volumetricRatio}';