tails-synchronize-data-to-new-persistent-volume-on-shutdown.service does not save APT cache at the right place

In t-p-s, the /live/persistence/TailsData_unlocked/apt/cache/ is used to store the APT cache, to be mounted on /var/cache/apt/archives/.

But at tails-synchronize-data-to-new-persistent-volume.service copy the APT cache into /live/persistence/TailsData_unlocked/apt/archives/, so the ASP offline feature is broken.

Parent Task: #14594 (closed)

Original created by @bertagaz on 15431 (Redmine)