stack: Store actual widget size, not preferred size
stack: Store actual widget size, not preferred size

This is just a cleanup commit, no actual bug.

grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita