Don't applyReady immediately if WCT is launching activity

In this case, we need to wait for the activity lifecycle
callbacks or else we just immediately make a no-op. This
is a temporary fix until we address readiness properly.

Bug: 294624260
Test: start transition w/ launchtask (eg. with fullscreen app,
      go to recents, start entering split w/ that app, "cancel"
      split by tapping app preview to launch it in fullscreen).
Change-Id: If0852d184fe440f52f91b489a786201f86e41d59