🧪 Add tests for get_rknn_model_type

[ManupaKDU]

🎯 What: Adds missing unit tests for get_rknn_model_type in frigate/util/rknn_converter.py.
📊 Coverage: Covered "jina-clip-v1-vision", "arcface-r100", "yolo" variants, and unsupported model path parsing. Test coverage for frigate/util/rknn_converter.py is improved, covering lines 46-57.
✨ Result: Enhanced test coverage and reliability for RKNN model compatibility utilities.

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PR created automatically by Jules for task 9431757256177787303 started by @manupawickramasinghe

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