This commit removes the outline from instances generated from an object
when in edit mode. This takes the change in aa13c4b386 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 treated as an instance internally, this fixes the way evaluated
meshes for curves objects have an outline, for example.
See the differential revision for a visual comparison.
Differential Revision: https://developer.blender.org/D14226
216a215ba5