[ONNX] Improve shape inference for Slice (#105755)
Previously, if 'starts', 'ends', or 'steps' was dynamic, then shape inference would give up, even for dimensions which are not being sliced.
This commit improves this by setting the output shape to be the same as the input shape for dimensions which are not being sliced. Add a new test to cover this case.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/105755
Approved by: https://github.com/thiagocrepaldi, https://github.com/BowenBao
