[lib][web] Add worker logic for adding search messages

Summary: issue: ENG-8645

Test Plan: Added an update_search_messages operation in processDBStoreOperations in redux-utils.js. Tested that updateMessageSearchIndex was run and no errors showed up in the web console and worker console

Reviewers: tomek, kamil, marcin

Reviewed By: kamil

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D12801