count Messages
suspend fun countMessages(beforeNs: Long? = null, afterNs: Long? = null, deliveryStatus: DecodedMessage.MessageDeliveryStatus = MessageDeliveryStatus.ALL, excludeContentTypes: List<FfiContentType>? = null, excludeSenderInboxIds: List<String>? = null, insertedAfterNs: Long? = null, insertedBeforeNs: Long? = null): Long