grpc-js-xds: Enable xDS affinity test

Author: murgatroid99

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

@@ -166,6 +166,7 @@ main() {
   cd "${TEST_DRIVER_FULL_DIR}"
   local failed_tests=0
   test_suites=(
+    "affinity_test"
     "api_listener_test"
     "baseline_test"
     "change_backend_service_test"