Fix cluster references

Co-authored-by: Sergii Tkachenko <[email protected]>

Author: murgatroid99

packages/grpc-js-xds/scripts/xds_k8s_lb.sh

@@ -139,8 +139,8 @@ main() {
   echo "Sourcing test driver install script from: ${TEST_DRIVER_INSTALL_SCRIPT_URL}"
   source /dev/stdin <<< "$(curl -s "${TEST_DRIVER_INSTALL_SCRIPT_URL}")"
 
-  activate_gke_cluster GKE_CLUSTER_PSM_SECURITY
-  activate_secondary_gke_cluster GKE_CLUSTER_PSM_SECURITY
+  activate_gke_cluster GKE_CLUSTER_PSM_LB
+  activate_secondary_gke_cluster GKE_CLUSTER_PSM_LB
 
   set -x
   if [[ -n "${KOKORO_ARTIFACTS_DIR}" ]]; then