Sparse CSR: add `convert_indices_from_csr_to_coo` (#66774)
Summary:
This PR adds conversion from CSR to COO.
Fixes https://github.com/pytorch/pytorch/issues/56959
cc nikitaved pearu cpuhrsch IvanYashchuk gchanan mruberry
Pull Request resolved: https://github.com/pytorch/pytorch/pull/66774
Reviewed By: zou3519
Differential Revision: D32288415
Pulled By: cpuhrsch
fbshipit-source-id: 683ba658dc46835fdf3c0e24645c0c2bb243b968
