client/gtk2: Add XTranslateCoordinates for GTK4 X11 coordinate
client/gtk2: Add XTranslateCoordinates for GTK4 X11 coordinate

GdkWindow had the absolute coordiante in the private class in GTK3
but the absolute coordiane no longer exists in GTK4 for Wayland.
Now get the toplevel window coordiante for the warkaround in GTK4
but the coordiante of the inner widgets is no longer available too.

BUG=https://gitlab.gnome.org/GNOME/gtk/-/issues/3024#note_987835

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