remove SlackGrowiBridging component

src/client/js/components/Admin/SlackIntegration/SlackGrowiBridging.jsx

@@ -1,16 +0,0 @@
-import React from 'react';
-import PropTypes from 'prop-types';
-
-const SlackGrowiBridging = (props) => {
-  return (
-    <>
-    </>
-  );
-};
-
-SlackGrowiBridging.propTypes = {
-  slackWorkSpaceName: PropTypes.string,
-  siteName: PropTypes.string,
-};
-
-export default SlackGrowiBridging;