should
Handles appboy schemed ("appboy://") urls in the HTML content WebViews. If the url isn't appboy schemed, then the url is passed to the attached IInAppMessageWebViewClientListener.
We expect the URLs to be hierarchical and have appboy equal the scheme. For example, appboy://close is one such URL.
Return
true since all actions in Html In-App Messages are handled outside of the In-App Message itself.