[2.4.8-beta2] Downgrade TinyMCE dependency from version 7 to version 6.8.5

Author: jayrangnani-gl

lib/web/mage/adminhtml/wysiwyg/tiny_mce/tinymceAdapter.js

@@ -207,8 +207,7 @@ define([
                 toolbar: this.config.tinymce.toolbar,
                 adapter: this,
                 'body_id': 'html-body',
-                license_key:'gpl',
-                xss_sanitization: false,
+
                 /**
                  * @param {Object} editor
                  */