message: fix typo in name of cluster-thanos flag error display name
diff: @@ -320,7 +320,7 @@ func main() {
  Endpoint: offClusterPrometheusURL,
  }
  - offClusterThanosURL := bridge.ValidateFlagIsURL("k8s-mode-off-thanos-prometheus", *fK8sModeOffClusterThanos)
  + offClusterThanosURL := bridge.ValidateFlagIsURL("k8s-mode-off-cluster-thanos", *fK8sModeOffClusterThanos)
  offClusterThanosURL.Path = "/api"
  srv.ThanosTenancyProxyConfig = &proxy.Config{
  TLSClientConfig: serviceProxyTLSConfig,
  