NIFI-14680 Add kafka.offset to Record FlowFiles from ConsumeKafka

[exceptionfactory]

Summary

NIFI-14680 Adds the kafka.offset attribute to FlowFiles produced from the ConsumeKafka Processor when configured with the Record strategy.

This addition aligns with current behavior for the Demarcator strategy, which writes the minimum offset to the kafka.offset attribute.

Additional changes include clarifying the description of the WritesAttribute annotations in ConsumeKafka and adjusting the Record integration test to send each Record separately for combination in a single FlowFile.

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  • JDK 21

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[pvillard31]

Thanks for the changes @exceptionfactory and making the description of the written attributes more consistent, merging