Desktop-first based drag-to-maximize

This CL changes the drag-to-maximize criteria from the static overlay
config to the display state of “desktop-first” where the TDA’s windowing
mode is freeform.

Flag: com.android.window.flags.enable_desktop_first_based_drag_to_maximize
Bug: 409423422
Test: DesktopFirstUtilsTest
Test: DesktopDisplayModeControllerTest
Test: DesktopTasksControllerTest
Change-Id: I379e7daaf5b935e6f11ad4485e37533cf0a3799f