[ONNX] Remove protocol dataclass (#85916)
Remove the `_WithOp` protocol because it is not used and causes the dataclass `GraphContext` to not be able to init in some python versions.
Reference to issue of dataclasses Inheriting from Protocol https://github.com/python/cpython/issues/89244
Pull Request resolved: https://github.com/pytorch/pytorch/pull/85916
Approved by: https://github.com/BowenBao, https://github.com/abock, https://github.com/thiagocrepaldi
