revert libero delta action change (Physical-Intelligence#351)

Author: kpertsch

src/openpi/training/config.py

@@ -302,11 +302,13 @@ def create(self, assets_dirs: pathlib.Path, model_config: _model.BaseModelConfig
         # apply a separate delta conversion (that's why it's commented out). Choose whether to apply this
         # transform based on whether your dataset uses ``absolute`` or ``delta`` actions out of the box.
 
-        # delta_action_mask = _transforms.make_bool_mask(6, -1)
-        # data_transforms = data_transforms.push(
-        #     inputs=[_transforms.DeltaActions(delta_action_mask)],
-        #     outputs=[_transforms.AbsoluteActions(delta_action_mask)],
-        # )
+        # TODO(karl): comment this out once we have updated the Libero checkpoints to not use
+        # the delta action transform
+        delta_action_mask = _transforms.make_bool_mask(6, -1)
+        data_transforms = data_transforms.push(
+            inputs=[_transforms.DeltaActions(delta_action_mask)],
+            outputs=[_transforms.AbsoluteActions(delta_action_mask)],
+        )
 
         # Model transforms include things like tokenizing the prompt and action targets
         # You do not need to change anything here for your own dataset.