Suppress spammy warnings

[daviswer]

Current code prints multiple warnings from each gpu at the start of training, which clutters up the log. Updates dataloader and process group constructors to eliminate these warnings, respectively:

/app/fms-fsdp/fms_fsdp/utils/dataloader_utils.py:27: UserWarning: To copy construct from a tensor, it is recommended to use sourceTensor.clone().detach() or sourceTensor.clone().detach().requires_grad_(True), rather than torch.tensor(sourceTensor).
  data_seq = torch.tensor(data_seq, dtype=torch.int)

and

[rank1]:[W Utils.hpp:135] Warning: Environment variable NCCL_ASYNC_ERROR_HANDLING is deprecated; use TORCH_NCCL_ASYNC_ERROR_HANDLING instead (function getCvarInt)

No practical effect on code behavior otherwise.