Expose SparseLengthsSum8BitRowwiseSparse to C10 (#47306)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/47306
Expose SparseLengthsSum8BitRowwiseSparse to PyTorch, since pt's 8bit embedding doesn't support pruning yet.
It's temporary solution to unblock the QRT test, not best for performance.
Test Plan: ci
Reviewed By: ashishenoyp
Differential Revision: D24709524
fbshipit-source-id: 725dfc9d803e4a555dd71fa5ab75dc175e671563
