MC-3693: Add WYSIWYG to banner preview

- Resolved issue where wysisyg is only appended to the first instance of banner

Author: Hwashiang Yu

app/code/Magento/PageBuilder/view/adminhtml/web/js/content-type/banner/preview.js

@@ -147,7 +147,7 @@ export default class Preview extends BasePreview {
         element.id = this.parent.id + "-editor";
 
         const config = this.config.additional_data.wysiwygConfig.wysiwygConfigData;
-        config.adapter.settings.fixed_toolbar_container = ".pagebuilder-banner-text-content";
+        config.adapter.settings.fixed_toolbar_container = "#" + this.parent.id + " .pagebuilder-banner-text-content";
 
         WysiwygFactory(
             this.parent.id,