[ONNX] Improve Expand shape inference (#69264)
Extend shape inference support for `Expand`, when value of argument `shape` is unknown. Infer the rank of the output of `Expand`, and set shape to dynamic, if shape of argument `shape` is known.
Without this, shape inference aborts, and falls back to the static shape provided by tracer, which is incorrect in many cases.
Co-authored-by: BowenBao <bowbaomicrosoft.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/72985
