Update nccl commit tag to head of v2.8 branch (#47603)
Summary:
Previous head of v2.8 branch was force-updated from `cd5a9b73c3028d2496666201588111a8c8d84878` to `31b5bb6f6447da98b9110c605465f9c09621074e`
Fixes https://github.com/pytorch/pytorch/issues/47529
Pull Request resolved: https://github.com/pytorch/pytorch/pull/47603
Reviewed By: seemethere, janeyx99
Differential Revision: D24832450
Pulled By: malfet
fbshipit-source-id: ea141b207d7d8e92300ba286cde3cda3773adf51
