NIFI-14072 - restore support for partial updates of labels

[pvillard31]

Summary

NIFI-14072 - restore support for partial updates of labels

This PR restores the support for partial updates at labels level. It was removed in #9526. The logic is restored but moved in the DAO code that is not used when it comes to changing flow versions. This way proper behavior is restored and the fix from #9526 is maintained to not break flow versioning when style is changing.

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Build

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  • JDK 21

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[exceptionfactory]

Thanks for correcting this @pvillard31, I noted one minor syntax detail, otherwise looks good.

[exceptionfactory]

Thanks @pvillard31, looks good! +1 merging