Update taskbar state when launcher pauses

With shell-transit, we need to defer updating state when resumed
(until we commit a transient launch state); however, for pause
this isn't necessary. In fact, now that taskbar exists in overview,
we must update state on-pause since the taskbar is no-longer
already-closed.

Bug: 253473765
Test: atest NexusLauncherTests:com.android.quickstep.TaplTestsQuickstep#testOverview
Change-Id: I347da03a211f5b2685f7b18666b2ebb93a1731ef