Unify list elements for all list types (#30777)
Summary:
Previously list elements were only unified for tensor lists.
This improves error messages and expands the unification logic
to include all types.
](https://our.intern.facebook.com/intern/diff/18837726/)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/30777
Pulled By: driazati
Differential Revision: D18837726
fbshipit-source-id: c4d275562a8429700987569426d694faa8f6002e
