Error when using Differential Diffusion with CustomSampler

Whenever I pass Differential Diffusion into Custom Sampler with mask, I get this error:
[IndexError: invalid index of a 0-dim tensor. Use tensor.item() to convert a 0-dim tensor to a Python number](https://stackoverflow.com/questions/56483122/indexerror-invalid-index-of-a-0-dim-tensor-use-tensor-item-to-convert-a-0-di)

Changing line 30 in nodes_differential_diffusion fixes issue
From:
current_ts = model.inner_model.model_sampling.timestep(sigma[0])
To:
current_ts = model.inner_model.model_sampling.timestep(sigma)

Not sure if it breaks anything so I didn't make any commits