Don't specify 1P Launcher3 type if 3P Launcher is active

Instead of referencing Launcher directly (which may not be
present when there's a 3P launcher), reference the lowest
common ancestor of Launcher and RecentActivity to avoid
ClassCastExceptions.

Test: Visually inspected that Pixel Launcher crash dialog
no longer pops up.
* Install 3P launcher
* In developer options enable "enable freeform windows"
* Restart phone for settings to take effect
* Try to use it on any app you have in recent tasks

Fixes: 135419782
Change-Id: Ie1f54880ab46956b23e253850ca7f79b161da9bd