As a user, I want to watch via star on mobile, so that I can easily watch a page for a short period of time .
**Acceptance criteria:**
* The user should be able to still watch a star permanently with existing behavior (i.e., click on star to watch permanently)
* The notification at the bottom should be changed to read: The user will first see the following message at the top: [page name] and its talk page have been added to your watchlist permanently
* The dropdown should be labeled with "Watchlist time period" and display the following options:
** Permanent (as default)
** 1 week
** 1 month
** 3 months
** 6 months
* If a temporary expiry was chosen, the following behavior should occur:
** The full star becomes half star (covered in T261970)
** Display a success message: [page name] and its talk page have been added to your watchlist [time period, such as "one week"]
** Adjust the watch state of the page to have an expiry
* If a temporary expiry is not chosen (i.e., the user keeps permanent selection):
** They will see original message notification
** The original dismissal behavior of the pop-up should remain in place
* Note: UX improvements will be covered in a separate ticket (T261997), and the bug related to only seeing the half star upon refresh will be covered in a separate ticket (T261970)