Register Sub-Layers creates map image layers and not feature layers

[simongis]

Enhancement Request:

As an Admin, I want to register each of the layers in my map services as feature layer items in my portal.

This is so that I can easily search for these layers in the Map Viewer, add more than one from the same service to the map, and also have the ability to change symbology of the feature layer.

The tool here appears to create map image layers, as opposed to feature layers.