As a Watchlist Expiry user, I want the pop-up to be OOUI, so that it can generate the option to watch temporarily.
**Background:** This is a sub-task of T248496. Please refer to this ticket for details. The purpose of this ticket is to implement the loading of the popup, replacing Toast (current behavior) with OOUI.
**Resources:**
* [[ https://meta.wikimedia.org/wiki/Community_Tech/Watchlist_Expiry | Watchlist Expiry project page ]]
* [[ https://wikimedia.invisionapp.com/public/share/8QYG7BMTJ#/screens/475685049 | Interactive mockup: Watch a page temporarily (via star) ]]
* [[ https://wikimedia.invisionapp.com/public/share/U5YGJG1RZ#/screens/475686737 | Interactive mockup: Unwatch a page (via star) ]]
**Acceptance Criteria:**
* The user should be able to watch a page via the star & generate OOUI message
** When a page is not being watched, the user can click the star to load the pop-up
** OOUI should be lazy loaded on click of the star, not on page load.
** OOUI pop-up should appear with success message (later augmented with expiry selection)
*** Success message: [page name] and its talk page have been added to your watchlist permanently
** The word "watchlist" in the pop-up should always link to the user's watchlist
* Message should be dismissible
** OOUI popup should vanish after [x] seconds.
** Hovering over the popup resets that count to vanish [x] seconds after mouseout.
* The user should be able to unwatch the page with toast message
** The user should still be able to unwatch the page by clicking the star
** Toast message appears as usual with the same message (no change)
**Visual Examples:**
//Temporarily watch a page via star, before selection made (note that this ticket does not include the drop-down, as shown in the mockup)//
{F31724546}
//Unwatch a page//
{F31718251}