Fix oci registry tests
Fix oci registry tests

These were relying on details of the remote-ls output.
We can avoid this by explicitly specifying what columns
we want.

Closes: #2409
Approved by: alexlarsson

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