EditChannelAdmin reactivates a previously kicked/banned member to Active
status but left BannedRights.ViewMessages set from the old ban, an
Active+banned-from-viewing state nothing else in the codebase expects.
TransferChannelOwnership's participant check trips on it and rejects the
transfer with PARTICIPANT_MISSING, even though the target is now a
visibly active admin.
Sync telesrv 36eda30 (feat(communities): implement Layer 228 community aggregates).
Skipped telesrv docs changes per public sync rules; normalized the public appearance seed label.
