[Observability AI] Add troubleshooting info for support case

[alaudazzi]

Summary

This PR:

• Adds a new section on Export conversations for support cases
• Adds a cross-reference in ## Known issues pointing to the new export section

Closes #5430

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Generative AI disclosure

1. Did you use a generative AI (GenAI) tool to assist in creating this contribution?

• Yes
• No

[github-actions]

🔍 Preview links for changed docs

• solutions/observability/ai/observability-ai-assistant.md

[github-actions]

✅ Vale Linting Results

No issues found on modified lines!

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[lucabelluccini]

Hello @alaudazzi - I need some feedback from engineering on this one. I've left a comment.

[alaudazzi]

Thank you @lucabelluccini!

I need some feedback from engineering on this one

Who should we ask?

[lucabelluccini]

Thank you @lucabelluccini!

I need some feedback from engineering on this one

Who should we ask?

Sorry Arianna, I've actually edited the review - I was testing it and the menu referenced was not showing up at all and I thought it had been removed.
It isn't the case, it is just showing up after the first "interaction" with the AI Assistant.
So you can disregard the request for engineering feedback.