remove protobuf from Dependencies.cmake for libtorch mobile build (#25958)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/25958
Should have cleaned up the remaining protobuf dependencies before landing PR #25896.
Test Plan: - CI build;
Reviewed By: dreiss
Differential Revision: D17296949
Pulled By: ljk53
fbshipit-source-id: 20c444e63900c7fa054db3cc757d3f18614af630
