Returns a `Tensor` to represent this feature in the input_layer().

def _get_dense_tensor(self, inputs, weight_collections=None, trainable=None):
    """Returns a `Tensor` to represent this feature in the input_layer()."""
    del weight_collections, trainable  # Unused.
    m = module.Module(self.module_spec, trainable=False)
    images = inputs.get(self)
    return m({"images": images})