This commit removes the outline from instances generated from an object
when in edit mode. This takes the change in aa13c4b386b1 a bit further,
with the idea that instance outlines are more like regular outlines.

Because evaluated object data that doesn't match the original object
type is internally treated as an instance, this fixes the way evaluated
meshes for curves objects have an outline, for example.

Before Object Mode	Before Edit Mode	After Object Mode	After Edit Mode