Use flatpak-ci-initiative.yml directly
flatpak-ci-initiative-sdk-extensions.yml might be removed in the future as noted here: https://gitlab.gnome.org/GNOME/citemplates/-/blob/master/flatpak/flatpak-ci-initiative-sdk-extensions.yml#L3
flatpak-ci-initiative-sdk-extensions.yml might be removed in the future as noted here: https://gitlab.gnome.org/GNOME/citemplates/-/blob/master/flatpak/flatpak-ci-initiative-sdk-extensions.yml#L3