[lib] Reduce removePeerUsersActionType in thread reducer

Summary:
issue: ENG-9634
In the thread reducer we want to use generateOpsAndProcessThreadUpdates which reduces delete account updates. In the future removePeerUsersActionType will be fully replaced by an update sent with processDMOpsActionType action. But this is tracked in ENG-4905

Test Plan: Tested by dispatching removePeerUsersActionType action. Tested that the user gets deleted: they get removed from threads, user store and aux user store.

Reviewers: tomek, kamil

Reviewed By: tomek

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D13740