Add `#pragma once` to CUDA foreach headers (#58209)
Summary:
Per the title, adding `#pragma once` to cuda headers related to foreach functions.
cc: ptrblck
Pull Request resolved: https://github.com/pytorch/pytorch/pull/58209
Reviewed By: ailzhang
Differential Revision: D28558620
Pulled By: ngimel
fbshipit-source-id: 195f68435999eb7409ba904daf6fc5f0962d375d
