Remove HBM logic from the UDFPS overlay

This change removes the high-brightness mode logic, and provides hooks
for the subclasses to implement this logic instead.

This also changes the layout of the overlay from being a fullscreen
window, to a window that's the exact size of the sensor.

Bug: 177563105
Test: atest UdfpsControllerTest
Change-Id: Ie5dd4ea862e07c862feb9ae09ed9c602b32849e1