Refactored the AddOliveMetadata ONNX pass to ensure all externaldata files (e.g., .bin, .xml) are preserved when adding metadata to ONNXmodels.Key changes:- Always copy entire input directory to output location to preserve  all external files alongside the main ONNX model- Simplified pass logic by treating all models as directory-based- Load ONNX models without external data to preserve file structure- Return directory-based ONNXModelHandler for consistent behaviorAdded comprehensive unit tests:- test_add_metadata_with_external_data_files: Verifies external  file preservation for directory-based models with mock .bin/.xml- test_add_metadata_single_file_to_directory_conversion: Ensures  correct metadata handling for single-file ONNX modelsThis fix addresses issues where external data files were lost duringmetadata addition, ensuring model integrity for ONNX/OpenVINO modelswith external dependencies.