Handle duplicate kinds in listener allowed kinds

[fabian4]

Proposed changes

Handle duplicate kinds in listener allowed kinds

Closes #2346

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Added a fix to handle duplicate kinds in listener allowed kinds 

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[github-actions]

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[fabian4]

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[sarthyparty]

Thanks for the PR and nice work @fabian4! Changes pretty much lgtm, just one quick question.

EDIT: I also tested the deduplication manually via building NGF and applying a gateway listener with duplicate kinds and it looks good

[shaun-nx]

Ran some manual tests on this like @sarthyparty did too
Looks good to me 🎉 nice work @fabian4 !

[sarthyparty]

🚀

[sarthyparty]

@fabian4 Actually per @ciarams87 comment, can you make the key of both the Group and the Kind for completeness?