a11y: Resume autoclick when hovering panel

Resume autoclick whenever the panel is hovered to allow the user to get
out of a paused state.

When the panel is a standard LinearLayout,the View api
setOnHoverListener() does not work for this use case becasuse of the
child button elements. When the button elements become hovered, the
LinearLayout panel considers that as an "ACTION_HOVER_EXIT" even though
the button is actually inside the panel.

Creating a subclass of LinearLayout is required to implement
onInterceptHoverEvent(). This allows the event from hovering of any
element part of the "ViewGroup" (i.e. the buttons) to be intercepted and
handled as desired.

Demo: http://b/397460424#comment2

Bug: b/397460424
Test: AutoclickTypePanelTest
Flag: com.android.server.accessibility.enable_autoclick_indicator
Change-Id: I05f8d8e77585086cb8d8933a5df6c9bbd61437bb