pytorch

2853c7da - Replace composite dispatch with `CompositeExplicitAutograd` (#64641)

Replace composite dispatch with `CompositeExplicitAutograd` (#64641) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/64641 `sum`, `mean`, and `norm` were ported to structured kernels in #61642, #61643, and #62711, respectively. Those PRs changed related overlads into composite kernels. However, their dispatch section remained the same, when they really should be marked as `CompositeExplicitAutograd`. This PR fixes this issue. Test Plan: Imported from OSS Reviewed By: ngimel Differential Revision: D30867122 Pulled By: ezyang fbshipit-source-id: b951aee41a3cab9ca546df826a285d60013e3b3a