feat: IPv6 connectivity support in NGINX One APIs

[defanator]

Proposed changes

Added the note about recently introduced IPv6 connectivity support for NGINX One APIs endpoints.

Checklist

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• I read the Contributing guidelines
• My branch adheres to the Git conventions
• My content changes adhere to the F5 NGINX Documentation style guide
• If my changes involve potentially sensitive information¹, I have assessed the possible impact
• I have waited to ensure my changes pass tests, and addressed any discovered issues

Footnotes

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[github-actions]

✅ All required contributors have signed the F5 CLA for this PR. Thank you!
_{Posted by the CLA Assistant Lite bot.}

[defanator]

I have hereby read the F5 CLA and agree to its terms

[mjang]

Thanks! I have some relatively minor suggestions.

[mjang]

Moving back to draft -- we need to test for confirmation (working in an internal issue)

[mjang]

Holding until test confirmation