Update ci-testing.yml

[glenn-jocher]

Remove keras==2.6.0 patch

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Improvement of CI testing workflow by refining dependency installation steps.

📊 Key Changes

• Unified pip install commands into a single line for installing required packages and extra libraries.
• Removed the explicit keras version installation, now relying on versions specified in requirements.txt.

🎯 Purpose & Impact

• Simplification: Consolidates installation steps to make the CI configuration cleaner and possibly slightly faster.
• Maintenance: Reduces the need to update the CI config when the keras version changes, as dependencies are managed directly within requirements.txt.
• Reliability: Enhanced consistency in CI tests can lead to more reproducible testing environments and fewer integration issues.

These adjustments ensure the CI process is more streamlined and maintainable, which can lead to a smoother development process and quicker identification of potential issues for contributors and maintainers of the repository.