Don't collapse the Shade when expanding a notification.

This CL prevents the Shade from collapsing if a notification expansion
animation is pending/running. It does so by:

1. Making sure that StatusBarNotificationActivityStarter#shouldCollapse
   is checked *after* ActivityLaunchAnimator#setLaunchResult is called.
2. Updating the clipped area of the parent of the notification that is
   expanding, if any.
3. Not moving the QS or the notification siblings while the animation is
   running.
4. Making sure that the notification is displayed above the QS.

See b/181654098#comment4 for before/after videos.

Bug: 181654098
Test: Manual; atest ActivityLaunchAnimatorTest ExpandableNotificationRowTest NotificationChildrenContainerTest NotificationStackScrollLayoutTest StatusBarNotificationActivityStarterTest

Change-Id: I5a7beb4dc4883ed2757e286c4b480f83709680f7