Remove `use_c10_dispatcher: full` lines added in the last couple days (#50769)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/50769
There were a couple new of these lines added in the last couple of days but they're not necessary anymore.
This PR removes them and also adds an assertion to make sure we don't add any more.
ghstack-source-id: 120133715
Test Plan: waitforsandcastle
Reviewed By: bhosmer
Differential Revision: D25961316
fbshipit-source-id: e2befc5b6215b42decb2acedcacfb50734857e2f
