Remove image content from repo context being uploaded to Opik

If images or badges appear in the readme of the repo, these are added as additional content logged to Opik and included in the content passed to the agent. This can be discarded/processed before being used as content for the agent. 

Ref image:

<img width="1184" height="927" alt="Image" src="https://github.com/user-attachments/assets/ae44a6cc-ec79-4370-8c4d-fcbd3cb30a63" />