Only let shortcuts respect insets due to device cutout

On devices with a cutout and rotateable lockscreen, there is the
possibility of the cutout covering the shortcuts, or moving up the
whole bottom area of the lockscreen. Allow the shortcuts to move up,
but leave the middle of the lockscreen in place.

Fixes: 326343596
Test: manual -- on device with rotateable lockscreen and inset, rotate
Flag: NONE
Change-Id: I32bff37cf75787a1ec05bbf8f56e4e56ff79da0c