Test if the persistent filesystem's root directory needs to be world-readable
Things like #7443 (closed) would not be an issue if
/live/persistence/TailsData_unlocked/ had e.g. permissions 0770. What
prevents us from doing this? Possibly, we might want to add an ACL to
grant the amnesia user read access to this directory, but it’s probably
not really needed, as the persistent directories are usually
bind-mounted to places that this user can read.