[lib, native] Introduce getThreadListSearchResults function for common web and mobile thread list logic

Summary: Introduced function for common thread list filtering logic, so it could be used also in web app.

Test Plan: Search on mobile app works correctly - exactly as before.

Reviewers: palys-swm, atul, benschac, ashoat

Reviewed By: palys-swm, benschac, ashoat

Subscribers: ashoat, Adrian, atul, karol-bisztyga

Differential Revision: https://phabricator.ashoat.com/D2885