Do not preload recents activity if it will be visible

Before, even if the launcher was not launched, RecentsAnimation would
start the activity in background as invisible. It would cause issue
because ensureVisibility would make it visible because there is no
opaque activity on top, while that may not be collected in any app
transition.

Now, in case the recents activity should be visible, we ignore the
 preload recents activity.

Bug: 193565751
Test: pass failed launcher test
Change-Id: I93f5a716177bcbf69f5e4d5915826bd9f61f53a4