Fixing "integration-k8s-leadership-tests"

[cryptoe]

There was a Cgroup mismatch issue:
Docker was using : systemd where as the older version of K3s (v1.21) and kubectl defaults to cgroupfs.
Hence:

• updated both kubectl and k3s to the latest version.
• updated setup_k8s_cluster.sh for easier debugging.

This run : https://github.com/apache/druid/actions/runs/16409555884/job/46361961829 has more details.

Jul 21 06:09:32 pkrvm4h0tjkhlvh k3s[3026]: E0721 06:09:32.283529    3026 server.go:288] "Failed to run kubelet" err="failed to run Kubelet: misconfiguration: kubelet cgroup driver: \"cgroupfs\" is different from docker cgroup driver: \"systemd\""