Search can crash the app if showCorrespondingWMSLayers is true and the result comes from a DocumentHandler document

[jacobwod]

Search can crash the app if showCorrespondingWMSLayers is true and the result comes from a DocumentHandler document.

The reason is that the "faked" featureCollection that comes from the DocumentHandler document lacks a corresponding OL layer. But we tried stuff like this:

if (layer.get("layerType") === "group")

… which, in case of undefined, crashed the app.