Standardize license headers in Python files

[pderrenger]

This PR updates all Python file headers to use a standardized license format. 🔄

Changes:

• 📝 Standardized header: # Ultralytics 🚀 AGPL-3.0 License - https://ultralytics.com/license
• 🧹 Ensures consistent spacing after headers
• 🔍 Applies to all Python files except those in venv

Learn more about Ultralytics licensing 📚

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

This PR updates licensing headers across all source files in the YOLOv5 repository for clarity and consistency.

📊 Key Changes

• Updated license headers from "Ultralytics YOLOv5 🚀, AGPL-3.0 license" to "Ultralytics 🚀 AGPL-3.0 License - https://ultralytics.com/license" in all files.
• Slight restructuring of some assert and error messages for readability and formatting.

🎯 Purpose & Impact

• Purpose:

  • Provide a consistent and clear reference to the open-source AGPL-3.0 license and the Ultralytics licensing page.
  • Enhance uniformity in licensing documentation across the codebase.

• Impact:

  • Helps users, developers, and contributors better understand licensing terms.
  • No functional changes—users will not experience any behavior or performance differences. 📜✨