cleanup: re-enable kms demo tests in universe domain (googleapis#15034)

Author: cuiy0006

ci/cloudbuild/builds/universe-domain.sh

@@ -26,11 +26,10 @@ export CC=clang
 export CXX=clang++
 
 if [[ -n "${UD_SA_KEY_FILE}" ]]; then
-  # TODO(#15021): Re-enable kms tests when kms is available from cloudbuild
-  # ud::bazel_run //google/cloud/universe_domain/demo:kms_demo \
-  #   "${UD_PROJECT}" "${UD_REGION}" "${UD_SA_KEY_FILE}"
+  ud::bazel_run //google/cloud/universe_domain/demo:kms_demo \
+    "${UD_PROJECT}" "${UD_REGION}" "${UD_SA_KEY_FILE}"
   ud::bazel_test //google/cloud/storage/tests:universe_domain_integration_test
-  # ud::bazel_test //google/cloud/universe_domain/integration_tests:impersonation_tests
+  ud::bazel_test //google/cloud/universe_domain/integration_tests:impersonation_tests
 else
   source module ci/etc/integration-tests-config.sh
   bazel run -- //google/cloud/universe_domain/demo:kms_demo \