Improve `GetBasketItemListDto` to set the BasketName as "Default"

plugins/Baskets/src/EasyAbp.EShop.Plugins.Baskets.Application.Contracts/EasyAbp/EShop/Plugins/Baskets/BasketItems/Dtos/GetBasketItemListDto.cs

@@ -1,13 +1,11 @@
 using System;
-using System.ComponentModel.DataAnnotations;
 
 namespace EasyAbp.EShop.Plugins.Baskets.BasketItems.Dtos
 {
     [Serializable]
     public class GetBasketItemListDto
     {
-        [Required]
-        public string BasketName { get; set; }
+        public string BasketName { get; set; } = BasketsConsts.DefaultBasketName;
         
         /// <summary>
         /// Specify the basket item owner user ID. Use current user ID if this property is null.