Update drag resizing to prioritize close button.

Removes the pilfer pointers call on ACTION_DOWN for drag handles, as
this prevented clicking on the close button in the area where the
button and the top right corner handle intersected. Instead, we add
pilfer calls to ACTION_MOVE and ACTION_UP/CANCEL events to prevent
click events triggering during a drag resize.

Because DesktopModeWindowDecorViewModel's EventHandler handles
MotionEvents before DragResizeInputListener's handler, this CL also
adds a check to ensure a drag reposition is not performed while a drag
resize handle is being touched. Previously this was avoided by
pilfering on ACTION_DOWN, before any ACTION_MOVE could be handled.

Lastly, this CL changes the timing of showing resize veil to first
ACTION_MOVE instead of ACTION_DOWN to prevent briefly showing the veil
while closing a task.

Bug: 318633921
Test: Manual, confirm that top corner handles can both handle button
clicks and drag resizes while still preventing input to tasks behind it.
Test: atest VeiledResizeTaskPositionerTest,
FluidResizeTaskPositionerTest

Change-Id: Ie3937d2a41de925c233d9474eb7495c5b8b0ac89