Make EasterEgg go edge-to-edge by changing the cutout mode

This CL changes the cutout mode of com.android.egg/.paint.PaintActivity
from shortEdges to always. Without changing this, the process will crash
when the edge-to-edge policy is enforced.

Bug: 309578419
Test: Run `adb shell am start -n com.android.egg/.paint.PaintActivity`
      and see if PaintActivity can be launched as expected.
Change-Id: I28a4c69defbddb45e7a5da5d0f16452bc1df75ce