Bring back functionality of using the default Portal basemap gallery for all users

[JPaulo]

We liked the functionality of configuring which basemaps users can see in the basemap gallery, no matter if a user is signed in to Portal or not. The current setup (at least in 10.8.1) where the gallery is different between public users and named users does not make sense. 

The change creates confusion in the configuration of the basemap gallery widget in WAB and JS apps. 

Before you can just do this:

Now you have to do this workaround:

It looks like it gives the same result... but it does not.