[tp] remove deprecated tp_mesh_dim arg (#121432)
This PR removes the deprecated tp_mesh_dim arg to prepare for release.
As we deprecated this arg for a while (by throwing deprecating
messages), we should remove it before the release
#suppress-api-compatibility-check
Pull Request resolved: https://github.com/pytorch/pytorch/pull/121432
Approved by: https://github.com/wz337
ghstack dependencies: #121431