[lib] First pass at removing LegacyThreadInfo from chat-selectors

Summary:
Part of https://linear.app/comm/issue/ENG-6366/rename-minimallyencodedrawthreadinfo-to-rawthreadinfo

We can't remove them all because we'll need to address thread-utils first. Will do that next.

Depends on D10644

Test Plan: flow

Reviewers: ashoat, ginsu, tomek

Reviewed By: ashoat

Differential Revision: https://phab.comm.dev/D10645