Fix recents crashing during docked stack resize.

Whether acitvity window should be preserved during the relaunch is
controlled by the activity manager and the existence of
non-client-decor should not affect it. For example, docked activities
will not have non-client-decor, but we would like to preserve them
anyway.

Bug: 24573657
Change-Id: I5d4852c3b7c26ac3ec1bbc105639f75b67d1d3ad