Fix quant modelproto error (#23322)

### Description
Fixing
[issue](#23268 (comment)).
Saving a `ModelProto` with `save_as_external_data=True` updates its
metadata, which could lead to issues later if not managed carefully.
Using a deepcopy to prevent such problems.

Author: xiaoyu-work

onnxruntime/python/tools/quantization/quant_utils.py

@@ -5,6 +5,7 @@
 # --------------------------------------------------------------------------
 from __future__ import annotations
 
+import copy
 import logging
 import os
 import tempfile
@@ -988,8 +989,9 @@ def load_model_with_shape_infer(model_path: Path) -> ModelProto:
 
 def save_and_reload_model_with_shape_infer(model: ModelProto) -> ModelProto:
     with tempfile.TemporaryDirectory(prefix="ort.quant.") as quant_tmp_dir:
+        model_copy = copy.deepcopy(model)
         model_path = Path(quant_tmp_dir).joinpath("model.onnx")
-        onnx.save_model(model, model_path.as_posix(), save_as_external_data=True)
+        onnx.save_model(model_copy, model_path.as_posix(), save_as_external_data=True)
         return load_model_with_shape_infer(model_path)