[lib] Update useResolvedThreadInfos to remove LegacyThreadInfo

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

We want to remove LegacyResolvedThreadInfo altogether.

To start we're updating useResolvedThreadInfos (and related functions) to only handle MinimallyEncodedThreadInfos.

This diff makes that change and addresses the flow issues that arose in lib. Will create separate diffs for web and native, the CI will fail for this diff. Personally would've preferred to include all of them in a single diff that passes CI, but will break it up.

[skip-ci]

Depends on D10655

Test Plan: flow

Reviewers: ashoat, ginsu, tomek

Reviewed By: ashoat

Differential Revision: https://phab.comm.dev/D10670