[Dev options][Wallpaper flag] Update all usage of enableDesktopWindowingWallpaperActivity
flag to use DesktopModeFlags

Test: Current tests pass
Bug: 348193756
Flag: com.android.window.flags.show_desktop_windowing_dev_option
Change-Id: Ib923286ca6e9ce9fbc94230eebccdbcadc9392b5
2 files changed