Update notebook readme and LLM usage

[RizwanMunawar]

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

A new notebook entry for Ultralytics YOLO model validation and results export has been added to the README. 🚀

📊 Key Changes

• Added a new row in the README table for "Ultralytics YOLO Model Validation and Results Export."
• Included links to documentation and a relevant discussion for more information.
• Noted that the Colab notebook and YouTube video are "Coming Soon."

🎯 Purpose & Impact

• Makes users aware that a dedicated notebook for model validation and exporting results is on the way.
• Provides quick access to documentation and community discussions, helping users learn about validation workflows.
• Signals ongoing improvements and upcoming resources, keeping the community informed and engaged. 📢

[UltralyticsAssistant]

👋 Hello @RizwanMunawar, thank you for submitting an ultralytics/notebooks 🚀 PR! This is an automated response to help with the review process. An Ultralytics engineer will also assist you soon.

To ensure your contribution is seamlessly integrated, please review the following checklist:

• ✅ Define a Purpose: Clearly explain the purpose of your fix or feature in your PR description, and link to any relevant issues. Make sure your commit messages are clear and concise.
• ✅ Synchronize with Source: Confirm your PR is up-to-date with the main branch of ultralytics/notebooks. If needed, click the 'Update branch' button or run git pull and git merge main locally.
• ✅ Ensure CI Checks Pass: Verify that all Ultralytics Continuous Integration (CI) checks have passed. Address any issues if checks fail.
• ✅ Update Documentation: Ensure any relevant documentation is updated for new or changed features.
• ✅ Add Tests: If applicable, include or update tests covering your changes, and confirm all tests pass.
• ✅ Sign the CLA: If this is your first Ultralytics PR, please sign our Contributor License Agreement (CLA) by commenting "I have read the CLA Document and I sign the CLA" on this PR.
• ✅ Minimize Changes: Limit your changes to the minimum necessary for your update. "It is not daily increase but daily decrease, hack away the unessential. The closer to the source, the less wastage there is." — Bruce Lee

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