Avoid crash on wrong output of systemctl version (bsc#1229539)

What does this PR do?

Backport of https://github.com/saltstack/salt/pull/66856

In some cases calling systemctl --version with salt.grains.core._systemd could return unexpected output what could cause IndexError exception preventing minion service from running.

What issues does this PR fix or reference?

Tracks https://github.com/SUSE/spacewalk/issues/25122

Previous Behavior

IndexError exception on starting minions service caused by unexpected response of systemctl --version

New Behavior

Normal minion start with just error message in the log about unexpected output.

Merge requirements satisfied?

[NOTICE] Bug fixes or features added to Salt require tests.

[ ] Docs
[ ] Changelog - https://docs.saltproject.io/en/master/topics/development/changelog.html
[ ] Tests written/updated

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Yes/No

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openSUSE / salt