[CodeGen] Generating invalid image preprocessing for NCHW models

[MadhurKumar004]

Location: compiler/code_generator.py

Description: CodeGenerator._generate_python_input_processing treats input_shape[1] and [2] as Height/Width. This breaks for NCHW models (ONNX/PyTorch).

Fix: Inspect the model format (via IR) and generate specific preprocessing code for NHWC vs NCHW.