[lib] Remove threadFrozenDueToBlock, threadOrParentThreadHasAdminRole and memberHadAdminPowers

Summary:
Last usage was removed in D12543, also removed functions where only usage was via threadFrozenDueToBlock

Depends on D12543

Test Plan: flow + searching codebase to make sure there are no remaining references.

Reviewers: ashoat

Reviewed By: ashoat

Differential Revision: https://phab.comm.dev/D12554