[Pass] Clear metadata

[titaiwangms]

https://github.com/microsoft/onnxruntime/blob/a28da4b90a17c9729c9448c5702c302e3bd2566b/onnxruntime/python/tools/transformers/dynamo_onnx_helper.py#L172-L179

[justinchuby]

There is also docstring that can be cleared