修复orderDto 空异常

src/Hotline.Share/Dtos/Order/OrderDto.cs

@@ -625,7 +625,7 @@ namespace Hotline.Share.Dtos.Order
 
         public List<RepeatableEventDetailOpDto> RepeatableEventDetails { get; set; } = new();
 
-        public List<OrderVisitDto> OrderVisits { get; set; }
+        public List<OrderVisitDto>? OrderVisits { get; set; }
 
         public List<FileJson>? FileJson { get; set; }