Update task top activity after applying launch flags

- When recycling a task complyActivityFlags() may clear the task and
  finish the task top activity, in this case we should act on the
  subsequent task top activity

Bug: 179905395
Test: atest NexusLauncherTests:TaplTestsNexus#testOverviewActions
      on a CF instance
Change-Id: Ic5db82b82ffe13641519c3cea032c6e46ef1423c