Speck does not render unless it is attached to a callback

[shammamah-zz]

Discovered while writing the documentation for Dash Bio. Although the component does not have to be an input to a callback after the setProps issue was solved by an update to dash_renderer (https://github.com/plotly/dash-renderer/blob/master/CHANGELOG.md#changed-1), Speck does not render (and the properties passed to it are not applied) if it is not the output of a callback.