Detect 3p launcher move-to-front during recents.

If entering recents with a 3p launcher below a translucent task,
the 3p launcher will remain visible the whole time. This means
that, upon "committing" to go home (swipe-to-home), the 3p
launcher task will be brought to-front rather than launched. If,
we don't check for this, the default behavior of Recents handler
is to cancel the current recents transition if it sees a
transition with unrecognized stuff that isn't related to it's
session.

So, add a check for 3p launcher moving-to-front and convert it
into an "open" so the rest of recents treats it as such.

Bug: 284195706
Test: add calendar widget to 3p launcher, open an event,
      swipe-to-home.
Change-Id: I81cd2a69858f4e20fe0bf86be94ca0e2af06fc28