You are returning a dict with two keys ("image" and "class").
If you are unwrapping it, data and label will contain the keys, which are strings:
batch = {'image': torch.randn(1),
         'class': torch.randn(1)}

data, labels = batch
print(data)
> image
print(labels)
> class

Create the data and label tensors via:
for batch in val_dataloader:
    data = batch['image']
    labels = batch['class']