`n_classes: 1` in info.json for 5 Contaminant datasets should be `2`

[rgeronimi]

The five Contaminant-detection datasets (Urbinati, 9.0–11.0 GHz) have "n_classes": 1 in their info.json. The value should be 2, given that:

• "task_type" is "binclass"
• the actual .npy targets contain two classes (0 and 1), balanced ~50/50 across all splits

Affected files in dataset-latest.zip:

Dataset folder	n_classes (current)	n_classes (expected)
Contaminant-...-9.0GHz(Urbinati)	1	2
Contaminant-...-9.5GHz(Urbinati)	1	2
Contaminant-...-10.0GHz(Urbinati)	1	2
Contaminant-...-10.5GHz(Urbinati)	1	2
Contaminant-...-11.0GHz(Urbinati)	1	2