Merge "Make the notif panel focusable during screen off so touch events don't...

Merge "Make the notif panel focusable during screen off so touch events don't go to the app behind." into sc-dev am: ce9883b6 am: 6810a423

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15097911

Change-Id: Ib94bc21cf23a2ba2626a1691e26c751f349b223c