Call GroupHelper when posting notification update with different channel

 Call GH#onNotificationPosted when the updated notification has a different channel, as it may result in regrouping to a new section.
 Only trigger ungrouping/cleanup in onNotificationPosted, grouping/regrouping will be handled automatically as the notification is treated as new after cleanup.

Flag: android.service.notification.notification_force_grouping

Test: atest GroupHelperTest NotificationManagerServiceTest
Bug: 382762909
Change-Id: Ia13fcfbabb9d1ed60095da9048d258f1f691fd94