a11y: Clear autoclick indicator after movement

Clear the autoclick indicator whenever the user moves the mouse enough
to reset the click timer.

Before & After demos: http://b/409788317#comment2

Bug: b/409788317
Test: AutoclickControllerTest
Flag: com.android.server.accessibility.enable_autoclick_indicator
Change-Id: Ie292456b2e2dda5566a9ec46d1c1a53146b70406