Refactor image loading in tests to use load_test_image helper (#47218)
* Refactor image loading in tests to use load_test_image helper
* Apply Ruff formatting
* Revert unintended formatting changes
* Remove unused COCO fixture URLs
* fix: Remove empty vision and pytesseract func
* Refactor COCO URLs to use load_coco_image helper and comment cleanup
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Co-authored-by: Tarek Ziade <tarek@ziade.org>