Explicitly request focus after button pressed

Don't use focusableInTouchMode, it was causing focus/clickability issues
when the device wasn't in touch mode.

Test: manually tap button (tap works first try)
Test: turn on talkback and toggle buttons, also try toggling QS tile
while on the Settings page - doesn't reannounce state
Fixes: 158717450
Change-Id: I785d0200dd61235aa3308a8588f9ee998e7cb6e5