Swap freeform vs non-freeform TO_FULLSCREEN heights.

Switches the heights used to determine the TO_FULLSCREEN drag zone to be
in line with the spec: when in freeform, use the 40dp value, otherwise
base it off status bar height.

Similarly, uses the status bar height for beginning drag-to-desktop
transition.

Bug: 329013327
Test: Manual; confirm heights are swapped when dragging in fullscreen
zone.

Change-Id: Iaa2d3fc35ba92d03522140537b817f808748f367