Fix binary auroc error

[VukW]

For binary classification, AUROC metric requires a proba just of the class 1, with shape of (N,) rather then (N,C) as for multiclass. https://lightning.ai/docs/torchmetrics/stable/classification/auroc.html#binaryauroc So, right now binary classification AUROCmetric should fail (at least, it always fails for me). We may check why CI tests work as expected btw...

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