If notifications can scroll at all, allow scroll up to status bar

Fixes: 190748504

Test: 1 notif => no scroll
Test: 2 notifs, just enough to scroll => scrolls up to status bar
Test: no scrollRange regressions with
- enough notifs to scroll up and cover qs completely
- inline reply to show IME

Change-Id: I8d2215d841b52df21a45293a23e7aff09b39c7ae