Unauthenticated namespace creation and RBAC injection via rancher-webhook FleetWorkspace mutating webhook

A Rancher FleetWorkspace admission path allowed side effects to occur in the Rancher webhook handler for versions 0.7.0 up to 0.7.10, 0.8.0 up to 0.8.7, 0.9.0 up to 0.9.6 and 0.10.0 up to 0.10.7. An unauthenticated attacker with network access to the in-cluster rancher-webhook service could submit a crafted admission payload and cause workspace-related Kubernetes objects to be created with attacker-chosen identity data.