[27/N] Desks: Add activation changes from startLaunchTransition

Fixes #startLaunchTransition to not only track the desk activation (via
DeskTransition.ActivateDesk as it previously did) but also run
addDeskActivationChanges() whenever the desk needs to be activated.

This fixes missing changes such as:
- home/wallpaper reordering
- bringing inactive tasks to front
- applying task-limit policy

Whenever we're entering desktop through this method.

Also implements "moveTaskToFront" adb command.

Flag: com.android.window.flags.enable_multiple_desktops_backend
Bug: 390692038
Bug: 393977224
Test: enter desktop, open 2 apps, move one to fullscreen, run the
"moveTaskToFront" command using the taskId of the task left in desktop -
verify the desktop was properly reactivated

Change-Id: I10e36a08e8edec37e48f31188d297ea3e968031e