[10/N] Desks: Let non-root organized leaves use launch bounds

Allows non-root, created-by-organizer tasks to use the launch bounds
calculated by LaunchParams, instead of always inheriting form the root
task.
Non-organized tasks are left unchanged, always inheriting from the root.

Flag: com.android.window.flags.enable_multiple_desktops_backend
Bug: 394189679
Test: with a desk active, open a new window from taskbar, verify it
opens with freeform bounds, not fullscreen

Change-Id: I5985242014e02e051fad98e89a38cf03cd096f66