Refactor derived authentication notifications with real events from C-API

[rorbech]

With https://github.com/realm/realm-core/pull/7302/files it looks like we can actually get proper user authentication event callbacks through the C-API. We could use this to improve the implementation that emitted derived events from https://github.com/realm/realm-kotlin/pull/1354/files.

[sync-by-unito]

➤ PM Bot commented:

Jira ticket: RKOTLIN-1029