Clear all action: remove all recents apps, not only the ones showing in

the panel

before this, for the pinch-in-to-clear-all action we were removing
only apps that were showing in the panel, not all apps from the activity
manager recents list.
So a new recents panel toggle were still showing other apps from the
list.

Now we remove all of them but not the favorites ones, to have
a real clear-all action

Change-Id: Iaac435999a92def528d5b2d2e11c4c09ddebc829