Hypershift: konnectivity proxy-server accepts agent connections without validating client certificates

A flaw was found in the Konnectivity proxy-server configuration for hosted control planes. The agent-facing listener was started without --cluster-ca-cert (and without token-based agent authentication), so client certificates were not validated. A remote attacker who can reach the Konnectivity cluster endpoint could connect as an unauthenticated agent, join the routing pool, and potentially proxy, inspect, modify, or drop control-plane-to-node traffic.