[native] Remove threadMembersWithoutAddedAshoat check for ThreadInfo

Summary:
After working on D9332, I looked around for other cases where we were passing a ThreadInfo to threadMembersWithoutAddedAshoat, since that is a no-op. I found one other such case, so I decided to remove it.

Depends on D9332

Test Plan: Careful reading and Flow

Reviewers: atul, rohan, michal

Reviewed By: atul

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D9333