Fixes icons in shelf scrolled due to exposed menu.

This change modifies NotificationStackScrollLayout to reset the exposed
menu state in the following cases:

- transitioning to AOD
- scrolling via a touch on the exposed notification
- shade height changing, causing footer to clip the exposed notification

This prevents the notification's icon from having its scrollX set (which
is how we keep it lined up with the translated notification) when it's
in the shelf.

Test: manual
Change-Id: Ie2d179c9275ec457ee46c6a40859310610a6d9d8
Fixes: 112304611