Update train.py import val as validate

[glenn-jocher]

Resolves zero-mAP issue.

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

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Refactoring validation call in training routine and renaming for clarity.

📊 Key Changes

• The val module is now imported as validate to enhance code readability.
• All instances where val.run() is called have been updated to validate.run().

🎯 Purpose & Impact

• These changes primarily improve code comprehension by providing a more descriptive name for the validation step.
• Readability of code could lead to fewer errors and better maintainability.
• The impact on end users should be minimal as this is an internal codebase quality improvement, with no direct effect on functionality or performance.