Fix is_colab()

[glenn-jocher]

@AyushExel @kalenmike

Signed-off-by: Glenn Jocher [email protected]

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Improved detection of Google Colab environment within the utility functions.

📊 Key Changes

• Modified the is_colab() function to check for the 'google.colab' module in sys.modules instead of searching for 'COLAB_GPU' in the environment variables.

🎯 Purpose & Impact

• Enhanced Accuracy: Detecting the Colab environment through sys.modules is more reliable than environment variables, which can potentially reduce false positives and negatives when determining the runtime environment.
• User Experience: This change ensures features that are specific to the Colab environment behave correctly, providing a smoother experience for users running YOLOv5 in Google Colab notebooks.
• Potential Impact: Users working on Google Colab should see no interruptions or improvements in functionality, while the codebase becomes slightly more robust and maintainable.