Fix flatpak-list --arch
Fix flatpak-list --arch

It was looking at the wrong part of the ref...

Closes: #2765
Approved by: mwleeds

matthiasclasen/flatpak,matthiasclasen/flatpak,flatpak/flatpak,flatpak/flatpak,flatpak/flatpak,matthiasclasen/flatpak,flatpak/flatpak,flatpak/flatpak,matthiasclasen/flatpak,matthiasclasen/flatpak