Making bouncer switch sides on double tap only

Currently this works only when multiuser switcher is not visible, i.e. when flag BOUNCER_USER_SWITCHER is false.

Fixes: 231351708
Test: in one handed bouncer mode, try double tapping on the other side and see if bouncer shifts only for double taps.
Change-Id: I272e765b5c7ed316ad791b335e082063232e987b