set default value for weight_sparsity in response selector to 0

Author: Ghostvv

rasa/nlu/selectors/response_selector.py

@@ -171,7 +171,7 @@ def required_components(cls) -> List[Type[Component]]:
         # The scale of regularization
         REGULARIZATION_CONSTANT: 0.002,
         # Sparsity of the weights in dense layers
-        WEIGHT_SPARSITY: 0.8,
+        WEIGHT_SPARSITY: 0.0,
         # The scale of how important is to minimize the maximum similarity
         # between embeddings of different labels.
         NEGATIVE_MARGIN_SCALE: 0.8,