improve error message

Author: FynnBe

bioimageio/core/model_adapters/_pytorch_model_adapter.py

@@ -29,7 +29,7 @@ def __init__(
         devices: Optional[Sequence[str]] = None,
     ):
         if torch is None:
-            raise ImportError("torch")
+            raise ImportError("failed to import torch")
         super().__init__()
         self.output_dims = [tuple(a.id for a in get_axes_infos(out)) for out in outputs]
         self._network = self.get_network(weights)