glitch: fix webpack build failure in columns_area.js (#1212)

Fixes #1212 by copying what works in the mainline flavor.

app/javascript/flavours/glitch/features/ui/components/columns_area.js

@@ -51,8 +51,8 @@ const messages = defineMessages({
   publish: { id: 'compose_form.publish', defaultMessage: 'Toot' },
 });
 
-@component => injectIntl(component, { withRef: true })
+export default @(component => injectIntl(component, { withRef: true }))
-export default class ColumnsArea extends ImmutablePureComponent {
+class ColumnsArea extends ImmutablePureComponent {
 
   static contextTypes = {
     router: PropTypes.object.isRequired,