add missing braces for format in rpc _to_worker_info (#31969)
Summary:
This was missing and resulted in the incorrect `name` passed into `_to_worker_info` not being printed out in the error message.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/31969
Differential Revision: D19331927
Pulled By: rohan-varma
fbshipit-source-id: e74d47daec3224c2d9b9da3c0a6404cfa67baf65
