[BE] Fix TORCH_WARN_ONCE (#95559)
It does not take a condition as first argument, unlike `TORCH_CHECK`
Test plan, run: ` python3 -c "import torch;print(torch.arange(1., 10.,device='mps').view(3, 3).trace())"` and observe no warning
Pull Request resolved: https://github.com/pytorch/pytorch/pull/95559
Approved by: https://github.com/Skylion007
