fix: add system test back (#39)

Author: arithmetic1728

tests/system/test_system.py

@@ -23,6 +23,7 @@ class TestKeyManagementServiceClient(object):
  def test_list_global_key_rings(self):
  project_id = os.environ["PROJECT_ID"]
 
+ # List key rings from the global location.
  client = kms_v1.KeyManagementServiceClient()
  parent = f"projects/{project_id}/locations/global"
  client.list_key_rings(request={"parent": parent})