Currently if an app has been renamed and you run "flatpak update" you
will be prompted to decide whether to install the new name of the app
(and uninstall the existing one). However, in such a situation
flatpak_installation_list_installed_refs_for_update() does not return
the app, and therefore gnome-software doesn't see any updates available
(except in the case where the installed commit is older than the commit
with the eol-rebase metadata).
So include end-of-life-rebased apps in the returned list. Patches to
make gnome-software update such apps properly are forthcoming.
I checked that the included unit test only passes with this patch to
libflatpak.