manual acknowledgement results in duplicate pubcomp

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- [x] Bug exists Release Version 1.2.5 ( Master Branch)
- [ ] Bug exists in MQTTv3 Client on Snapshot Version 1.2.6-SNAPSHOT (Develop Branch)
- [ ] Bug exists in MQTTv5 Client on Snapshot Version 1.2.6-SNAPSHOT (Develop Branch)

If this is a bug regarding the Android Service, please raise the bug here instead: https://github.com/eclipse/paho.mqtt.android/issues/new

**ISSUE DESCRIPTION**
Setting manual acknowledgement to true and calling the message arrived complete method results into duplicate pubcomp and the connection gets disconnected. In short, manual acknowledgement is not possible.

**SNIPPET TO REPRODUCE**

```java

var client = ...;

client.setManualAcks(true);

client.setCallback(new MqttCallback() {
...
@Override
public void messageArrived(String topic, MqttMessage message) {
...
client.messageAriveComplete(message.getId(), 2);
...
}
...
});

client.subscribe(...);

```

**Result**

```bash
Creating MqttPubComp due to manual ACK: MqttPubComp [returnCode=0, properties=MqttProperties [validProperties=[...]]]
Creating MqttPubComp: MqttPubComp [returnCode=0, properties=MqttProperties [validProperties=[...]]]
MqttDisconnectResponse [returnCode=0, reasonString=null, userProperties=null, serverReference=null, exception=Connection lost (32109) - java.net.SocketException: Connection reset]
```

Start with the Java client's manual-acknowledgement path around setManualAcks(true), messageArrived, and messageAriveComplete(message.getId(), 2), then reproduce the supplied snippet on release 1.2.5. Trace the two logged MqttPubComp creations; done means one acknowledgement is produced and the connection remains established.

Written by the indexing model from the issue text.