ANYCUBIC I3 MEGA Filament sensor support with cap/lid

This accessory prevents the filament sensor on the Anycubic I3 Mega from getting disconnected from its expected location. This accessory slides around the filament sensor (with the magnet attached; no alteration required) and keeps it where it's expected to be.

I loved the original implementation. However, the sensor support (the printed part) would occasionally get loose and felt on the floor. I added a cap to prevent this from happening.