Do not apply minimal size for fullscreen task

ActivityInfo.WindowLayout is used for multi-window modes. The bounds
in fullscreen mode are inclined to be computed based on the parent
for the appropriate appearance.

Fixes: 152178928
Test: atest TaskRecordTests#testFullScreenTaskNotAdjustedByMinimalSize
      atest ManifestLayoutTests

Change-Id: Ia33fc0d6986b6f34f01d8bc06626b07161f12cbf