Fix using wrong component in ColumnBackButtonSlim

app/javascript/flavours/glitch/components/column_back_button_slim.js

@@ -1,7 +1,7 @@
 import React from 'react';
 import { FormattedMessage } from 'react-intl';
 import PropTypes from 'prop-types';
-import Icon from 'mastodon/components/icon';
+import Icon from 'flavours/glitch/components/icon';
 
 export default class ColumnBackButtonSlim extends React.PureComponent {