Handle running task launch properly in desktop mode

- Move logic from KeyboardQuickSwitchViewController to handle
  bringing desktop tasks to front, and still support recent
  tasks for non-desktop mode.

Flag: com.android.launcher3.enable_recents_in_taskbar
Test: manually launch tasks from the Recents section in both
Desktop mode and full screen mode (running vs recent)
Bug: 315354060

Change-Id: I0520351b4d0095a3538c6165acd82a7b4c45a5e2