Intercept swipe up touches

When NSSL is not a child of NPVC, certain touches will never reach it
as they are now being handled by NSSL first. This primarily includes
swipe up on NSSL, which should dismiss the lockscreen or show the
bouncer.

Flexiglass will eventually replace most of this handling. For now,
move handling up to the parent and delegate back to NPVC, to avoid
a major risky refactoring of touch handling that will only be needed
temporarily.

Bug: 288068119
Test: NotificationShadeWindowViewControllerTest NotificationPanelViewControllerTest
Change-Id: I59538b46f4f87d11ec96aa32884eda1254f8aa0d