Additional Software is not saving target release

When installing a package with a target version (for example sl/unstable) only sl is save to /live/persistence/TailsData_unlocked/live-additional-software.conf.

Related issues

Related to #15822 (closed)
Related to #16290 (closed)

Original created by @sajolida on 16298 (Redmine)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information