feat: Add support for pip cache origin files

[sahilnyk]

Fixes #4220

Adds a handler to parse origin.json files found in .cache/pip/wheels/ directories. Extracts package name, version, SHA-256 hash, and download URL from the pip cache metadata. The existing PypiWheelHandler already handles the .whl files in the same directories.

Tasks

• Reviewed contribution guidelines
• PR is descriptively titled 📑 and links the original issue above 🔗
• Tests pass -- look for a green checkbox ✔️ a few minutes after opening your PR
  Run tests locally to check for errors.
• Commits are in uniquely-named feature branch and has no merge conflicts 📁
• Updated documentation pages (if applicable)
• Updated CHANGELOG.rst