Fixed issue with test_kwargs_loss

[vfdev-5]

Fixes #2240

Description:

• Fixed CI issue with test_kwargs_loss

Check list:

• New tests are added (if a new feature is added)
• New doc strings: description and/or example code are in RST format
• Documentation is updated (if required)

[sdesrozis]

Switch to reduction sum works fine too

loss.update((y_pred, y, {"weight": torch.tensor([0, 0, 0], dtype=torch.float), "reduction": "sum"}))