messaging_hook was removed along with smpp (#559), but POST and PUT
/Applications still pass the request body straight into the INSERT/UPDATE.
Clients that still send messaging_hook (even as null) get a 500:
"Unknown column 'messaging_hook' in 'field list'".
Drop the field from the request body so older clients keep working.
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>