[Location sharing] Live location screen

Figma: https://www.figma.com/file/uthEK6xuo9hSQRdWvPAre5/Location-Sharing?node-id=473%3A48575

TODO:
- [ ] Show all live locations on map with a pin
- [ ] Pin color should be the same as user name color
- [ ] tap on pin center the pin in the screen
- [ ] If one user, center the map on the user
- [ ] If multiple user, try to show all pins
- [ ] Bottom sheet
- [ ] iOS 15 native component: https://sarunw.com/posts/bottom-sheet-in-ios-15-with-uisheetpresentationcontroller/
- [ ] Below iOS 15: Show 2 items and use a show more button
- [ ] Bottom sheet content:
- [ ] Reusable cells with an extra "stop sharing" action for current user
- [ ] Tap on cell show user location
- [ ] Tap on a pin show annotation view with share action
- [ ] On share action show system share sheet (UIActivity)

No files, tests, or entry points are named. Start by reviewing the linked Figma design and the checklist, then identify the existing location-sharing screen in the repository. Done means the map, pins, bottom sheet, location selection, stop-sharing action, annotation share action, and iOS-version behavior match the specified requirements.

Written by the indexing model from the issue text.