Add NMS threshold checks

[glenn-jocher]

PR asserts IoU and Confidence thresholds lie between 0.0 and 1.0.

🛠️ PR Summary

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🌟 Summary

Improved input validation for non-maximum suppression in YOLOv5.

📊 Key Changes

• Added checks to ensure the confidence threshold (conf_thres) and intersection over union threshold (iou_thres) are between 0.0 and 1.0.

🎯 Purpose & Impact

• 🔒 Enhanced Robustness: Ensures the non-max suppression function only accepts valid threshold values, preventing potential errors or unexpected behavior during object detection.
• ✅ Better User Guidance: Provides clear error messages if the user inputs invalid thresholds, making it easier for users to debug issues.
• 🛠 Code Reliability: These defensive programming checks contribute to overall code quality and reliability of the YOLOv5 framework.