Bear extruder body with separate sensor insert

This is a sliced up version of the Bear Extruder body that separates the part surrounding the filament sensor into a separate piece. This allows the extruder body to be printed in any color, and print only the part around the filament sensor itself in black.

I printed them as two separate pieces in two different colors, but they could also be used to print a single two color piece with an MMU.

When I printed them separately I did not scale the insert at all, so it was a tight fit into the