Fix legacy "container_title" metadata properties

[AndrewIsh]

Some instances still have “container_title” illrequestattributes sitting around. These should be “title”. (We use “title” for the container and “article_title” for the item of interest). There is a fallback in the UI that will display container_title if it exists, so display is correct. It would require a migration script in core Koha to address this.