fix no dataloader printing

qadence/ml_tools/train_grad.py

@@ -147,6 +147,7 @@ def loss_fn(model: torch.nn.Module, data: torch.Tensor) -> tuple[torch.Tensor, d
                     loss, metrics = optimize_step(
                         model, optimizer, loss_fn, dataloader, device=device
                     )
+                    loss = loss.item()
 
                 # single epoch with DictDataloader using a single iteration method
                 # DictDataloader returns a single sample of the data