a11y: Fix autoclicking when hovering panel

Attempting to click a button on the autoclick panel should always
peform a normal left click. This did not work while in the two click
modes: Dragging & Scrolling.

To resolve this, at the beginning of the click execution explicitly set
the click type to AUTOCLICK_TYPE_LEFT_CLICK if the autoclick panel is
hovered.

Also reformat tests to use common initializer function.

Bug: b/395094903
Test: AutoclickControllerTest
Flag: com.android.server.accessibility.enable_autoclick_indicator
Change-Id: I292c3496fd926ce2405ca9af59ffbcbd1f14a842