[native] stop persisting messageStore.threads via redux-persist

Summary:
ENG-3743

We have this data in SQLite now.

Depends on D9682

Test Plan: Try closing and opening the app multiple times to make sure there are no weird errors.

Reviewers: atul

Reviewed By: atul

Subscribers: ashoat, tomek, wyilio

Differential Revision: https://phab.comm.dev/D9683