Though the Watchlist is now disabled by default, the "Share page by email" template shows links to the Watchlist

Though we disabled the WatchList by default, its script service remains available, therefore allowing emails sent through the "Share page" function to display: "Add this page to your personal watchlist", with a link.

IMO we should either remove this sentence or provide an alternative for the notification center.

The logic of this code is available here : https://github.com/xwiki/xwiki-platform/blob/2f718a96a9971f1cc9ee01e0651c19aebbb4ac9f/xwiki-platform-core/xwiki-platform-sharepage/xwiki-platform-sharepage-ui/src/main/resources/XWiki/SharePage.xml#L383