Clean up customize_changeset in DB

No, there is not a way to disable customize_changeset posts from being created. These customize_changeset posts are created with the auto-draft status in the same way that a post gets created with the auto-draft status whenever you click on “Add New” in the admin. Note that because the auto-draft status is used, any such posts will get automatically deleted after 1 week. See wp_delete_auto_drafts().