W&B: Fix sweep

[AyushExel]

fixes #5386 introduced by adding ROOT path objects in argparse defaults

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Enhanced type casting in Weights & Biases sweep configuration.

📊 Key Changes

• 👩‍💻 Implemented explicit string conversion for sweep parameters: weights, cfg, data, hyp, and project.

🎯 Purpose & Impact

• 🎨 Ensures consistent parameter types, preventing potential bugs related to type mismatches.
• ☑️ Users can expect more reliable executions of hyperparameter sweeps when using Weights & Biases with YOLOv5.

[glenn-jocher]

@AyushExel PR is merged. Thank you for your contributions to YOLOv5 🚀 and Vision AI ⭐