Invalidate the pipeline list after HUN disappearing animation ends

Issue: a HUN is unpinned by the pipeline during the HUN disappearing
animation, which leads to interrupted animation when the HUN is in a
group. A previous change: 28056592 fixed this issue by leaving the HUN
pinned while during the disappearing animation. This change adds a step
to invalidate the list after the animation stops to allow the
notification to be sorted to the right section.

Bug: 354250568
Flag: com.android.systemui.notification_group_hun_removal_animation_fix
Test: NotificationStackScrollLayoutControllerTest
Change-Id: Ibb4899d8211850033288256c1565dd98ffca0bef