Fix windowless snapshot surface drawing with mismatch configuration.

For close task animation, there should attach the windowless surface to
the task, instead of activity. Because previous activity could inside
an adjacent task fragment.

Bug: 274997067
Flag: EXEMPT bugfix
Test: launch task from an adjacent embedded activity. Trigger back
gesture and verify the windowless surface should cover entire task.

Change-Id: I465b676fcb5daede45b21bba2ac30a900523ac20