[Bug 57456] Wine wayland scaled window is positioned on the left, not centered

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=57456

--- Comment #3 from Shmerl  ---
Pinged KWin developers, they said this is planned but will take a long time to
implement due to complexity of the spec.

Wine can do this itself too. Quoting:
> do it like other Wayland client that scales things in fullscreen - black 1x1 subsurface for the background + viewporter to scale the window(s) themselves

If it's too complex for Wine as well, I guess KWin users will have this broken
until later.