Fixed Nexus Pro Barrel Adapter with N-Strike Lug

The original model did not have enough overlap where it widened to the N-strike attachment portion. This resulted in the print snapping very easily at that point. I have thickened the design slightly at that point. It still works just fine with the Nerf attachments I tested on it. I also flipped the design upside-down as it printed much nicer this way in my opinion.