fix(notifications): Fix null references to notification types

aspnet-core/modules/realtime-notifications/LINGYUN.Abp.Notifications.Application/LINGYUN/Abp/Notifications/AbpNotificationsApplicationAutoMapperProfile.cs

@@ -15,6 +15,8 @@ public class AbpNotificationsApplicationAutoMapperProfile : Profile
                 if (src != null)
                 {
                     var dataType = Type.GetType(src.NotificationTypeName);
+                    if (dataType != null)
+                    {
                         var data = Activator.CreateInstance(dataType);
                         if (data is NotificationData notificationData)
                         {
@@ -22,6 +24,7 @@ public class AbpNotificationsApplicationAutoMapperProfile : Profile
                             return notificationData;
                         }
                     }
+                }
                 return new NotificationData();
             }));
     }