Cleanup workaround for rke2-metrics-server upgrade
This remove the rke2-metrics-server-fix-old-pods unit which had been added in commit 60cb1771 which was part of !2961 (merged) to handle a corner case breaking the upgrade from Sylva 1.1.1, not necessary anymore now that Sylva 1.2 is behind us.
Edited by Thomas Morin