Merge "notification stack scroller doesn't need a11y focus" into sc-dev am:...

Merge "notification stack scroller doesn't need a11y focus" into sc-dev am: 49c7bc66 am: 0e3a87bc

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15692791

Change-Id: Ia19906725f64633e57feb8dc6c02ed834395b0ee