[PyTorch] Remove unnecessary dispatcher.h include in torch/library.h (#51162)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/51162
It's unused.
ghstack-source-id: 120427120
Test Plan: CI
Reviewed By: bhosmer
Differential Revision: D25859010
fbshipit-source-id: 7bb21312843debaedaa6a969727c171b2bb0e6b2
