[BUG] Unable to export to ONNX due to torch.onnx._export being deprecated

[Snailed]

Describe the bug
The following code produces an error:

import timm
from timm.utils.onnx import onnx_export

model_name = "bat_resnext26ts.ch_in1k"
timm_model = timm.create_model(model_name, exportable=True)
timm_model.eval()
onnx_model = onnx_export(
    model=timm_model,
    output_file=f"{model_name}.onnx"
)

results in

Traceback (most recent call last):
  File "[file-path].py", line 7, in <module>
    onnx_model = onnx_export(
                 ^^^^^^^^^^^^
  File "[dir-path]/venv/lib64/python3.12/site-packages/timm/utils/onnx.py", line 83, in onnx_export
    torch_out = torch.onnx._export(
                ^^^^^^^^^^^^^^^^^^
AttributeError: module 'torch.onnx' has no attribute '_export'. Did you mean: 'export'?

To Reproduce
Steps to reproduce the behavior:
0. Install python 3.12.8

1. pip install torch==2.6.0 timm==1.0.14 onnx==1.17.0
2. Run the above code

Expected behavior
The code should export the model without errors (most likely by using torch.onnx.export instead of torch.onnx._export

Desktop (please complete the following information):

• OS: Linux, RHEL 8
• TIMM version: 1.0.14

Additional context
I tried replacing _export with export and it worked for me.

[rwightman]

@Snailed fixed it, I was hoping they'd leave the old one in there as it provided a useful output that the export() does not, ah well... in any case once the PR linked above is merged should be fine, fixed a small issue with the image size input too.