onnxruntime

[VitisAI] support memory buffer contains the TensorProto external data (#22042)

### Description
Extend VitisAI EP `tensor_proto_as_raw` API to support memory buffer
containing the TensorProto external data


### Motivation and Context
For reduce peak memory usage, VitisAI EP need support ORT format model
and setting session option
`session.use_ort_model_bytes_for_initializers` for enable directly use
the model bytes for initializers.

Co-authored-by: mingyue <mingyue@xilinx.com>