CHW-4803 ClientCredentialConflict

client credential fields are invalid or conflict with an existing record; verify client_id, client_type, and expiry_date

Default message: client credential fields are invalid or conflict with an existing record; verify client_id, client_type, and expiry_date
HTTP status: 400 (client)

Problem. Create or update clashed with an existing record or was otherwise invalid. Cause. Either the client_id is already taken (create) or a field value violated validation (e.g. unsupported client_type, malformed RFC3339 expiry_date). Fix. Pick a different client_id, or correct the invalid field. HTTP 400.