Notification history a11y fixes

- When clicking the expand/collapse button to see the posted
notifications from an app in the last 24 hours, refocus accessibility on
the button so the entire button (contentDescription + clickability) are
announced. Previously only the contentDescription update was being
announced.

- Fix local context menu of NotificationHistory elements by calling the
super method in performAccessibilityAction

Test: manual
Fixes: 153396313
Fixes: 153518629
Change-Id: I3d847ec1f2b72dcf411c6c7c7fe2dc061ccfde26