Change signature for torch.poisson (#45656)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/45656
Test Plan: Imported from OSS
Reviewed By: gmagogsfm
Differential Revision: D24078609
Pulled By: ansleyadelaide
fbshipit-source-id: 97a95b08334ed0d710e032a267b940c2fc9f7f40
