[ONNX] Update embedding_bag export (#44693)
Summary:
Export of embedding bag with dynamic list of offsets.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/44693
Reviewed By: malfet
Differential Revision: D23831980
Pulled By: bzinodev
fbshipit-source-id: 3eaff1a0f20d1bcfb8039e518d78c491be381e1a
