Add link to old editor to the sidebar

[MAILPOET-2549]

assets/js/src/form_editor/components/sidebar.jsx

@@ -28,6 +28,9 @@ SidebarHeader.propTypes = {
   ]).isRequired,
 };
 
+const oldEditorUrl = new URL(window.location.href);
+oldEditorUrl.searchParams.set('legacy', 1);
+
 export default () => {
   const activeTab = useSelect(
     (select) => select('mailpoet-form-editor').getSidebarActiveTab(),
@@ -74,6 +77,13 @@ export default () => {
         </ul>
       </SidebarHeader>
       {activeTab === 'form' ? <FormSettings /> : <BlockSettings />}
+      <p className="mailpoet_old_form_editor_link">
+        {MailPoet.I18n.t('editorIsUsingGutenberg')}
+        <br />
+        <a href="mailto:quentin@mailpoet.com">{MailPoet.I18n.t('giveFeedback')}</a>
+        {' '}
+        <a href={oldEditorUrl.toString()}>{MailPoet.I18n.t('useOldEditor')}</a>
+      </p>
     </div>
   );
 };