[User Switcher] Remove falsing check for a11y.

The user switcher on the bouncer has a bunch of falsing checks. Check to
see if the click that is performed is from an accessibility action. If
this is the case, we do not perform a falsing check.

Test: Add a unit test. Used voice access and switch access to open the
user switcher and select an item in that list.
Bug: 221370490, 222211112

Change-Id: Ie9fce53ce11b68dc10f5c2513d3c6a600c51fafa