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, which triggers the spin motion, the notification at the bottom, and the star becomes fully filled)
* 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 notification should have blue text in the bottom right corner, which states: "CHANGE DURATION."
* If the user clicks on the blue text, the bottom sheet should appear with the following options:
** Permanently (as default)
** 1 week
** 1 month
** 3 months
** 6 months
* Bottom sheet is same as sheet displayed when user tries to watch when logged off (see screenshot example in comments)
* If a temporary span was chosen, the following behavior should occur:
** The full star rotates and becomes half star (see half star details in T248495)
** 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 span is not chosen (i.e., the user keeps permanent selection):
** They will see original message notification
Visual examples:
**Watching a page**:
|Click star to watch page|Star spins to show loading|Blue star indicates that the page is watched|Toast notification informs the user that the page is watched|
|--|--|--|--|
|{F31793135,size=full}|{F31793137,size=full}|{F31793139,size=full}|{F31793141,size=full}|
**Watching a page temporarily**:
|Toast notification has a way to change time duration|Clicking 'Change duration' brings up //bottom sheet//|When someone picks a different duration the star starts spinning|Half star indicates that the page is temporarily watched|
|--|--|--|--|
|{F31793141,size=full}|{F31793143,size=full}|{F31793145,size=full}|{F31793149,size=full}|
**Unwatching a page**: Clicking on the star or the half star icon unwatches the page.