[lib] Render UserInfosHandler

Summary: issue: ENG-8235

Test Plan: Tested that when user connects to a new keyserver (and assuming processNewUserIDsActionType was dispatched, adding userinfow with missnig ids to the store), the handler fetches missing usernames and they get inserted into the user store

Reviewers: tomek, kamil

Reviewed By: tomek

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D12220