`SocialShare` is dependent on `sketches-host` which will give some unknown bugs

[asimqt]

Component SocialShare is dependent on the config value sketches-host. If the value doesn't accessible at state.qt.config["sketches-host"] normally because dev forget to whitelist that, this will throw invalid link like https://www.facebook.com/sharer.php?u=undefined/corporate-lifestyle/2010/01/01/power-lunch.

TODO:
Make the prop required and fail gracefully if the sketches-host not available.