fix kerasmodel

[SangbumChoi]

Since there is some deprecation of keras model usage I updated the following logic

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Enhanced TensorFlow model export functionality.

📊 Key Changes

• Introduced a new KerasModel class for model export.
• Modified the export process to use KerasModel instead of directly calling tf_model.predict.
• Changed the export format for Keras models to .h5 instead of TensorFlow's default format.

🎯 Purpose & Impact

• Improved Usability: Simplifies the TensorFlow model export process by encapsulating configurations within a KerasModel class.
• Consistency: Ensures the exported Keras models are saved in a more universally accessible .h5 format.
• Flexibility: Facilitates better management of model configurations and predictions, making the codebase more modular and user-friendly.