[CD][Alt+Tab] Show apps from all desktops for KQS on CD

- Even without multiple desktops, apps that are moved to connected display show up in separate desktop task.
- Further changes may be required to launch a desktop after multiple desktops is implemented.

Bug: 382762871
Flag: com.android.launcher3.enable_alt_tab_kqs_on_connected_displays
Test: manually built and run the CUJ
Change-Id: If104c67d95a1ec3de404998b06352edfa02c0f09