[QNN Quant] Handle external data for QNN preprocessing/quant

[adrianlizarraga]

Description

• Adds parameters to qnn_preprocess_model() to allow saving the new model with external data.
• Updates get_qnn_qdq_config() to:
  • Load model without external data (it is not needed)
  • Return a quantization configuration with use_external_data_format set to True if the model has external data or if the model is >= 2GB.

Motivation and Context

Update QNN quantization to better handle large models that use external data.