fix 价格默认获取菜单中的设置

Src/Dlhis.Basic/Dishes/Response/DishesDetailResponse.cs

@@ -35,7 +35,7 @@ public class DishesDetailResponse
     /// <summary>
     /// 单价
     /// </summary>
-    public decimal Price { get; set; }
+    public decimal? Price { get; set; }
 
     /// <summary>
     /// 剩余数量
@@ -53,7 +53,7 @@ public class DishesDetailResponse
             {
                 return CurrentUnits.ToObject<List<string>>();
             }
-            return new () { "个" };
+            return new() { "个" };
         }
     }