fix 多重名No映射问题

Src/Dlhis.External/Appointment/Dto/AppointmentReceiveItemDto.cs

@@ -58,12 +58,12 @@ public class AppointmentReceiveItemDto : IValidatableObject
     /// <summary>
     /// 访客开始
     /// </summary>
-    public DateTime DoorStart { get; set; }
+    public DateTime? DoorStart { get; set; }
 
     /// <summary>
     /// 访问结束
     /// </summary>
-    public DateTime DoorEnd { get; set; }
+    public DateTime? DoorEnd { get; set; }
 
     /// <summary>
     /// 进入车间
@@ -95,7 +95,7 @@ public class AppointmentReceiveItemDto : IValidatableObject
                 yield return new ValidationResult($"{Name}门岗区域不可为空", new[] { nameof(ApplyWorkplaceAreas) });
             }
 
-            if (DoorStart >= DoorEnd)
+            if (!DoorStart.HasValue || !DoorEnd.HasValue || DoorStart >= DoorEnd)
             {
                 yield return new ValidationResult($"{Name}门禁来访时间有误", new[] { nameof(DoorStart) });
             }