Fix sshd service missing on resolute

[bytestream]

The script is exiting early because of this combination:

• set -e is active — any non-zero exit code aborts the script immediately
• mkdir /var/run/sshd fails with File exists — the openssh-server package already created it during installation

I've changed mkdir to mkdir -p, so that it succeeds silently if the directory already exists.

I've also removed the || true which is what was swallowing the script failures. It was introduced in #235 but the correct fix is to replace the one-liners so that the condition doesn't exit 1

Closes #666

[bytestream]

@Theaxiom this should be good to merge and tag 🙏🏼