CloudPubSubSourceTask fails to ACK messages in Kafka 4.0 due to deprecated commitRecord method

[Lance726]

Is your feature request related to a problem? Please describe.

In Kafka 4.0, the SourceTask#commitRecord(SourceRecord record) method has been removed. Our current implementation only overrides this now-removed method, which causes subscription messages to never be acked in Kafka 4.0 source connectors. This creates a critical issue where messages are processed but never properly acknowledged.

Describe the solution you'd like

We need to add an implementation for the new method signature in Kafka 4.0:
SourceTask#commitRecord(SourceRecord record, RecordMetadata metadata)
This would allow our connector to properly acknowledge messages in Kafka 4.0 while maintaining backward compatibility with previous versions.

Describe alternatives you've considered

None.

Additional context
https://issues.apache.org/jira/browse/KAFKA-18294
https://archive.apache.org/dist/kafka/4.0.0/RELEASE_NOTES.html