Kubeconfig exec plugin execution in OSAC operator console proxy

OSAC operator is a Kubernetes operator. In the affected revision identified as 8220502, the `console-proxy` `RemoteConfigResolver` parses Kubernetes Secret kubeconfig data with `clientcmd.RESTConfigFromKubeConfig` without sanitizing the resulting `rest.Config`. An attacker who can create or modify a Secret labeled `osac.openshift.io/remote-cluster-kubeconfig`: "true" in a namespace where the proxy's RoleBinding grants Secret read access can supply `users[].user.exec`. When `rest.TransportFor` builds the HTTP transport for an upstream WebSocket connection, client-go invokes that exec credential plugin, spawning an arbitrary process as the osac-`console-proxy` service account inside the pod. Attacker-controlled `clusters[].server` also enables server-side request forgery from the proxy pod. Remote and auto VM cluster modes are affected, with auto the default; exclusively `local` mode does not read kubeconfig Secrets and is unaffected. The credential-plugin execution path is patched in commit 7e4222b; that patch does not address the described server-address SSRF path.