Update ZipFile to context manager

[glenn-jocher]

Also reject __MACOSX and .DS_Store files from unzipping.

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Refactoring of ZIP file extraction methods for cleaner and more maintainable code.

📊 Key Changes

• Removed direct ZipFile imports and usages in dataloaders.py, downloads.py, and general.py.
• Added a new unzip_file function in general.py to handle ZIP extraction.
• Updated all the instances where ZIP files were extracted using ZipFile to now use the new unzip_file function.
• Removed old Google Drive download function and helpers which are no longer needed.

🎯 Purpose & Impact

• The purpose of these changes is to centralize and simplify the process of unzipping files, which enhances code readability and maintainability. 🛠
• Users should experience no functional change, but the codebase is cleaner and less prone to bugs when handling ZIP file extractions. 📁
• Removal of deprecated Google Drive download code reduces clutter and potential confusion about supported download methods. 🧹