[lib] Refactor user reducers

Summary:
issue: ENG-6485
incrementalStateSyncActionType, processUpdatesActionType and processServerRequestsActionType are actions dispatched for one keyserver. They should not be changing currentUserInfo or userStore, unles the keyserver is the authoritative keyserver and relyingOnAuthoritativeKeyserver is true

Test Plan: Tested that for clients set up to rely on the authoritative keyserver incremental state sync updates currentUserInfo and userStore

Reviewers: michal, kamil, ginsu

Reviewed By: michal

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D11315