NIFI-14257: Adding additional scopes for ListenSlack on Message Events and new WritesAttribute

[ncover21]

Add additional scopes for "Receive Message Event" event type in ListenSlack connector:

• FileChangedEvent
• MessageChangedEvent
• ReactionAddedEvent

Add flowFile attribute for event type to route on.

Summary

NIFI-14257

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  • JDK 21

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[pvillard31]

Thanks for the contribution @ncover21 !

The change LGTM and I'm +1 assuming the checks are green. However I did leave a comment regarding additional event types that could be worth considering as part of this change.

[pvillard31]

+1, will merge assuming checks are green