Switch display windowing mode when display connected

This CL allows DEFAULT_DISPLAY to be a freeform display when any other
display is connected in extended mode. When the display is connected in
mirror mode, no behavior change is expected.

Flag: com.android.window.flags.enable_display_windowing_mode_switching
Bug: 374849026
Test: DesktopTasksController
Change-Id: I2abface6596dc58e5d5c13d3b675a9f43bf47376