Enable NCCL_DESYNC_DEBUG when TORCH_DISTRIBUTED_DEBUG=DETAIL (#83881)
Automatically enable `NCCL_DESYNC_DEBUG` when `TORCH_DISTRIBUTED_DEBUG` is set to `DETAIL`.
Saving user from setting two env variables.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/83881
Approved by: https://github.com/malfet, https://github.com/rohan-varma, https://github.com/H-Huang
