In preparation for some virtual desktop refactor for display mode emulation (https://gitlab.winehq.org/wine/wine/-/merge_requests/5057)
-- v2: win32u: Don't assume that the primary adapter is always first. win32u: Only consider active monitors in monitor_from_rect. win32u: Only consider active monitors for virtual screen rect. win32u: Only consider active monitors for clone detection. win32u: Deduce monitor device flags from their adapter.