clearMessages

@param messageIds Message unique ID List, at most 20
```kotlin
========================================
val params = ClearMessagesParams(timestamp = 0, policy = MessageOperationPolicy.LOCAL_REMOTE)
channel.clearMessages(params) { error ->
    if (error == null) {
        Based on given Send Timestamp, respectively Get This When point in time Before and After specified Count message.
    }
}

val params = GetMessagesAroundTimeParams(* sentTime = targetMessage.sentTime,
val params = ClearMessagesParams(timestamp = System.currentTimeMillis() - 86400000)
channel.clearMessages(params) { error ->
    // ...
}