Bug#930334: libfm-qt6: archivers.list adjustment to fix xarchiver compress integration

[Amy Kos]

To fix pcmanfm-qt 'right click on a file - compress' ability with xarchiver,
at least as long lxqt-archiver is not available.

Upstream libfm bug also applies to libfm-qt:
https://github.com/lxde/libfm/issues/35