Reduced GroundingDataset annotation unpacking speed

[Lornatang]

Reduce IO latency caused by multiple unpacking when faced with a large number of annotations

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Improved dataset handling by reorganizing captions for cleaner and more efficient processing. 🛠️

📊 Key Changes

• Refactored code to directly assign caption = img["caption"] before using it in label extraction logic.
• Simplified and clarified how category names (cat_name) are pulled from captions during annotation processing.

🎯 Purpose & Impact

• Purpose: To enhance code readability and maintainability by removing redundancy in caption handling.
• Impact: This change ensures smoother, more efficient dataset operations, which is great for both developers working on the code and users expecting swift and reliable annotation processing. 🚀

[sentry-io]

🔍 Existing Issues For Review

Your pull request is modifying functions with the following pre-existing issues:

📄 File: ultralytics/data/dataset.py

Function	Unhandled Issue
get_labels	ValueError: PosixPath('.') has an empty name path... Event Count: 5
get_labels	PermissionError: [Errno 1] Operation not permitted: '/content/drive/.shortcut-targets-by-id/1Kevj-bsv2CmtRnaGIR2wK... ... Event Count: 3
get_labels	ValueError: not enough values to unpack (expected 3, got 0) ultralytics.data.dataset in... Event Count: 2
get_labels	EOFError: No data left in file numpy.lib.npyio in... Event Count: 2

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[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 73.73%. Comparing base (2aac80d) to head (fdc1c87).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
ultralytics/data/dataset.py	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #18382      +/-   ##
==========================================
+ Coverage   73.70%   73.73%   +0.03%     
==========================================
  Files         129      129              
  Lines       17278    17279       +1     
==========================================
+ Hits        12735    12741       +6     
+ Misses       4543     4538       -5     

Flag	Coverage Δ
Benchmarks	34.88% <0.00%> (+0.03%)	⬆️
GPU	38.30% <0.00%> (-0.01%)	⬇️
Tests	67.52% <0.00%> (-0.01%)	⬇️

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[UltralyticsAssistant]

🎉 PR Merged! Huge thanks to @Lornatang for leading this improvement, with valuable insights from @Laughing-q and @glenn-jocher. Your collaborative effort to simplify and refine dataset handling ensures faster, cleaner, and smarter processes for everyone. 🚀✨

As Leonardo da Vinci once said, "Simplicity is the ultimate sophistication." This work embodies that spirit by making the code more elegant and impactful. Your contributions today will ripple out into countless projects, empowering developers and creators alike. Bravo! 🙌