fix: remove flash saying JS is disabled

common/app/routes/Challenges/Preview.jsx

@@ -1,54 +1,20 @@
-import React, { PureComponent } from 'react';
-import PropTypes from 'prop-types';
-import { connect } from 'react-redux';
+import React from 'react';
 
 import ns from './ns.json';
-import { isJSEnabledSelector } from './redux';
-import {Alert} from 'react-bootstrap';
-
 
 const mainId = 'fcc-main-frame';
 
-const mapStateToProps = state => ({
-  isJSEnabled: isJSEnabledSelector(state)
-});
-const mapDispatchToProps = null;
-const propTypes = {
-  isJSEnabled: PropTypes.bool
+const Preview = () => {
+  return (
+    <div className={ `${ns}-preview` }>
+      <iframe
+        className={ `${ns}-preview-frame` }
+        id={ mainId }
+      />
+    </div>
+  );
 };
 
-export class Preview extends PureComponent {
-  render() {
-    const {
-      isJSEnabled
-    } = this.props;
-    return (
-      <div className={ `${ns}-preview` }>
-        {
-          !isJSEnabled && (
-            <div className='js-alert-wrapper'>
-              <Alert
-              bsStyle='info'
-              className={ `${ns}-preview-js-warning` }
-              >
-                JavaScript is disabled. Execute code to enable
-              </Alert>
-            </div>
-          )
-        }
-        <iframe
-          className={ `${ns}-preview-frame` }
-          id={ mainId }
-        />
-      </div>
-    );
-  }
-}
-
-Preview.propTypes = propTypes;
 Preview.displayName = 'Preview';
 
-export default connect(
-  mapStateToProps,
-  mapDispatchToProps
-)(Preview);
+export default Preview;

common/app/routes/Challenges/challenges.less

@@ -186,14 +186,6 @@
   .max-element-height();
   width: 100%;
   overflow-y: hidden;
-
-  .js-alert-wrapper {
-    .max-element-height();
-    z-index: 5;
-    position: fixed;
-    width: 100%
-  }
-
 }
 
 .@{ns}-preview-frame {