Restore code that was deleted but it is needed

[MAILPOET-2625]

assets/css/src/components/formEditor/components/_sidebar.scss

@@ -85,3 +85,7 @@ $gutenberg-control-border-color-focus: #007cba;
     margin: 8px 0;
   }
 }
+
+.mailpoet_sidebar_note {
+  padding: 16px;
+}

assets/css/src/mailpoet-plugin.scss

@@ -1,8 +1,6 @@
 @import 'components/mixins';
-
 @import '../../../node_modules/select2/dist/css/select2';
 @import '../../../node_modules/spectrum-colorpicker/spectrum';
-
 @import 'components/automaticEmails';
 @import 'components/datepicker/datepicker';
 @import 'components/dynamicSegments';
@@ -30,9 +28,7 @@
 @import 'components/discounts';
 @import 'components/reviewRequest';
 @import 'components/stats';
-
 @import 'components/importExport';
-
 @import 'components/newsletterEditor/mixins/transitions';
 @import 'components/newsletterEditor/variables';
 @import 'components/newsletterEditor/common';

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

@@ -74,7 +74,7 @@ export default () => {
         </ul>
       </SidebarHeader>
       {activeTab === 'form' ? <FormSettings /> : <BlockSettings />}
-      <p className="mailpoet_old_form_editor_link">
+      <p className="mailpoet_sidebar_note">
         {MailPoet.I18n.t('editorIsUsingGutenberg')}
         <br />
         <a href="mailto:quentin@mailpoet.com">{MailPoet.I18n.t('giveFeedback')}</a>