Add transient notification views of group children to the child container, not directly to the row.

Ever since the introduction of the new pipeline, we have been removing adding the transient child to the ExpandableNotificationRow instead of the NotificationChildrenContainer due to a trivial oversight.  This works nearly all of the time because ExpandableViews track their transient container from which they can be removed at the end of their animation.  However, there are some situations where animations end abruptly, and transient views are cleaned up through traversal.  In this case we were only checking the NotificationChildrenContainer which would allow the transient children in the ExpandableNotificationRow to stay around forever.

We had a single "Transient Views" output at the end of the NSSL's dump() but that didn't include views which were child groups, so this change also adds a dump of transient views added to NotificationChildrenContainer.  There is no dump for ENR transient views, because there should not be any.

Fixes: 260191323
Test: atest ExpandableNotificationRowControllerTest
Merged-In: Ib5722ee5e6f5ae46902f276bd2bca7d6544e32a2
Change-Id: Ib5722ee5e6f5ae46902f276bd2bca7d6544e32a2