fix: ants registration 2.1.0 collapse files

ants registration does not generate collapsed files if composite transforms are written

Author: satra

nipype/interfaces/ants/registration.py

@@ -709,7 +709,7 @@ def _list_outputs(self):
                 outputs[
                     'reverse_invert_flags'].insert(0, reverseInverseMode)
                 transformCount += 1
-        else:
+        elif not self.inputs.write_composite_transform:
             transformCount = 0
             isLinear = [any(self._linear_transform_names == t)
                         for t in self.inputs.transforms]