Add CUJ_DESKTOP_MODE_EXIT_MODE_ON_LAST_WINDOW_CLOSE to launcher side

Move the CUJ to where the actual animation is taking place, so we can
target the correct surface/leash.

Bug: 374214290
Flag: NONE jank logging
Test: manual

Change-Id: Iccb30ff7ceee84b68428606575e1b8588eeb8aa9