remove unnecessary property

Author: sevmag

src/graphnet/models/data_representation/data_representation.py

@@ -75,6 +75,8 @@ def __init__(
             )  # noqa: E501 # type: ignore
         self._input_feature_names = input_feature_names
 
+        self.nb_inputs = len(self._input_feature_names)
+
         # Set data type
         self.to(dtype)
 
@@ -96,11 +98,6 @@ def __init__(
         else:
             self.rng = default_rng()
 
-    @property
-    def nb_inputs(self) -> int:
-        """Return the number of input features."""
-        return len(self._input_feature_names)
-
     @property
     def nb_outputs(self) -> int:
         """Return the number of output features."""