Fix build_from_data in ModelComparisonApproximator

Author: elseml

bayesflow/approximators/model_comparison_approximator.py

@@ -103,7 +103,7 @@ def build(self, data_shapes: dict[str, tuple[int] | dict[str, dict]]) -> None:
         self.built = True
 
     def build_from_data(self, adapted_data: dict[str, any]):
-        self.build(keras.tree.map_structure(keras.ops.shape(adapted_data)))
+        self.build(keras.tree.map_structure(keras.ops.shape, adapted_data))
 
     @classmethod
     def build_adapter(