[tensorboard] Fix function input parameter for add_hparams (#31301)
Summary:
closes https://github.com/pytorch/pytorch/issues/30943
both parameters in add_hparams are mandatory.
cc sanekmelnikov orionr
Pull Request resolved: https://github.com/pytorch/pytorch/pull/31301
Differential Revision: D21069761
Pulled By: natalialunova
fbshipit-source-id: 1a12f6760fa9676d11901fa85aa91f4f9fff976d
