Notif pipeline: call on UpdateFinished() callback after adding a child.

This used to be called in
NotificationViewHierarchyManager#updateNotificationViews, but in the new
pipeline world we no longer use that and instead rely on
RootNodeController now. Give the callback a heads up after
adding a child.

Bug: None
Test: Build
Change-Id: I4a55fdc59d405bc552f47d14d6ccafa0fb9e042f

packages/SystemUI/src/com/android/systemui/statusbar/notification/collection/render/RootNodeController.kt

@@ -40,6 +40,7 @@ class RootNodeController(
 
     override fun addChildAt(child: NodeController, index: Int) {
         listContainer.addContainerViewAt(child.view, index)
+        listContainer.onNotificationViewUpdateFinished()
     }
 
     override fun moveChildTo(child: NodeController, index: Int) {