message: Update WeightedCategoricalColumn to ensure categorical column input is sparse
diff: @@ -3979,9 +3979,10 @@ class WeightedCategoricalColumn(
  """Applies weights to tensor generated from `categorical_column`'."""
  weight_tensor = transformation_cache.get(self.weight_feature_key,
  state_manager)
  - weight_tensor = self._transform_weight_tensor(weight_tensor)
  - return (transformation_cache.get(self.categorical_column, state_manager),
  - weight_tensor)
  + sparse_weight_tensor = self._transform_weight_tensor(weight_tensor)
  + sparse_categorical_tensor = _to_sparse_input_and_drop_ignore_values(
  + transformation_cache.get(self.categorical_column, state_manager))
  + return (sparse_categorical_tensor, sparse_weight_tensor)
  @deprecation.deprecated(_FEATURE_COLUMN_DEPRECATION_DATE,
  _FEATURE_COLUMN_DEPRECATION)
  