[lib] Inline reduceUpdatesCurrentAsOf

Summary:
issue:https://linear.app/comm/issue/ENG-5349/inline-reduceupdatescurrentasof
processUpdatesActionType is dispatched only from UpdateHandler when a message comes to a socket. Sockets are keyserver specific, so the data is also keyserver specific

Test Plan: Tested logInActionTypes and processUpdatesActionType. Assuming the rest works by symmetry (see the deleted file for how it was before)

Reviewers: michal, kamil, ginsu

Reviewed By: michal

Subscribers: ashoat, tomek, wyilio

Differential Revision: https://phab.comm.dev/D9763