Enable shade_window_goes_around for desktop experience dev option

This enables the flag, but changes the display policy to "default display" only.

Bug: 362719719
Bug: 414767865
Test: DragDownNotificationShadeOnOtherDisplay
Flag: com.android.systemui.shade_window_goes_around
Change-Id: I75e82cbf730ce798ea3870a18fed96409183793d