Revert "build-aux/flatpak: use sassc from wrapdb"
This reverts commit cac0cb7f.
This doesn't work since CI currently mixes flatpak-builder and the host git repo and doesn't download the gtk sources, so all subprojects are missing.
This reverts commit cac0cb7f.
This doesn't work since CI currently mixes flatpak-builder and the host git repo and doesn't download the gtk sources, so all subprojects are missing.