Removes the Experience Builder Demo script

Closes #3501190

project_template/recipes/xb_demo/content/xb_page.yml

-# This file is scaffolded into XB's `content` directory, which will
-# allow the contributed Default Content module to import it when XB
-# ss installed. This should be moved into the `drupal_cms_starter`
-# recipe when XB is a production dependency of Drupal CMS.
-_meta:
-  version: '1.0'
-  entity_type: xb_page
-  uuid: 20354d7a-e4fe-47af-8ff6-187bca92f3f7
-  default_langcode: en
-default:
-  status:
-    -
-      value: true
-  owner:
-    -
-      target_id: 1
-  title:
-    -
-      value: Experience Builder
-  components:
-    - tree: '{"a548b48d-58a8-4077-aa04-da9405a6f418": []}'
-      props: '{}'
-  path:
-    -
-      alias: /xb-demo
-      langcode: en
-  created:
-    -
-      value: 1735191284
-  revision_translation_affected:
-    -
-      value: true