[Weblate] Silence systemcheck I028
Originally created by @hefee on #17381 (Redmine)
As we are doing manual backups, we can and should disable
`weblate.I028`
systemcheck:
https://docs.weblate.org/en/weblate-3.9.1/admin/backup.html#manual-backup
Feature Branch: https://salsa.debian.org/hefee/puppet-tails:hefee/17381-silence-systemcheck-I028