fix null异常问题

Src/Dlhis.Basic/Device/Services/Implements/DevicePermissionService.cs

@@ -796,7 +796,7 @@ public class DevicePermissionService : IDevicePermissionService
         var userNos = tripInfos.Select(x => x.UserNo).Distinct().ToList();
         var result = await GetAssignDeviceCodesInternalAsync(userNos);
 
-        foreach (var tripInfo in tripInfos)
+        foreach (var tripInfo in tripInfos.Where(x => x.UserNo.IsPresent()))
         {
             var myDeviceCodes = result[tripInfo.UserNo].SelectMany(x => x.Codes);