[backport v2022 <- v2023dev3] sample-image-production: Write os-release before cleaning up root

The /etc/os-release file is edited in the chroot environment (chroot: true), but that chroot env cannot be accessed after the "Reset rootfs before deploying OSTree" step (chroot is failing because /etc/resolv.conf is missing)

It also makes sense to edit /etc/os-release before running the "OSTree commit" step to include the correct /etc/os-release in the ostree commit. So the editing of /etc/os-release ("Customize image version metadata" step) is moved right before that.

Fixes: apertis-issues#151 (closed)

This is a backport of !533 (merged)