fix : Correct image path in deep research agents notebook

[BarnOwl5]

Fixed the incorrect image path so the diagram renders properly in the notebook.

Summary

• Updated the image reference from a broken relative path to the correct one.
• Ensures the diagram displays properly in examples/deep_research_api/introduction_to_deep_research_api_agents.ipynb.

Motivation

• The previous image path was broken, causing the diagram to not render on GitHub.
• This fix improves documentation readability for users referencing the Deep Research API.

[BarnOwl5]

Just a small fix here! It would mean a lot to me if you could check it out whenever possible. 🥹✨