Bump aiosendspin to 3.0 (#2924)

Bump aiosendspin to 3.0 (#2924)

* Bump aiosendspin to 2.0

Adapt to breaking changes in aiosendspin:
- Change event listener callbacks from async to synchronous
- Change start_server advertise_host to advertise_addresses

* fix: handle client disconnect during pending unregister wait

Check if client still exists after waiting for pending unregister,
preventing player registration attempts for disconnected clients.

* chore(deps): bump aiosendspin to 3.0.0

---------

Co-authored-by: Maxim Raznatovski <nda.mr43@gmail.com>