Update threat-intel-integrations.asciidoc

[tchen-tc]

New ThreatConnect Threat Intelligence integration with Elastic was released.

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[nastasha-solomon]

Thanks for opening this, @tchen-tc! I'll take over the PR from here, and run the necessary technical and editorial reviews.

[tchen-tc]

@nastasha-solomon Thank! Do I need to update this branch since it says it is out of date?

[nastasha-solomon]

Hey, @tchen-tc! 👋🏼 You're good! The page you updated needs to be fixed in other branches as well, so I'll likely close this PR and open a new one to re-apply the necessary changes to the appropriate areas in our docs.

[nastasha-solomon]

Applying this change in #5338.