refactor: convert class component to functional"

superset-frontend/src/SqlLab/components/QueryAutoRefresh/index.jsx

@@ -16,7 +16,7 @@
  * specific language governing permissions and limitations
  * under the License.
  */
-import React, { useState, useEffect } from 'react';
+import { useState, useEffect } from 'react';
 import PropTypes from 'prop-types';
 import { bindActionCreators } from 'redux';
 import { connect } from 'react-redux';