live-additional-software.conf is given wrong permissions when it's updated by tails-additional-software

With an ISO build with 8dd945efef3e4f47f11742862cf34b098ae42cc2

Boot from USB with network and admin password with no configured persistent storage
Install a package with APT
Confirm you want to create the persistent storage
Enter passphrases and confirm
Wait for t-p-s to finish and close it

/media/tails-persistence-setup/TailsData/live-additional-software.conf is 0600

live-persist rightfully detects it’s not 0644 on next boot and disable ASP.

Original created by @bertagaz on 15430 (Redmine)

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