That little brass tube is pressed into the pot metal that the carb body is made of. If you try some Marine-Tex epoxy it may stay put.
Also, score the outside of the tune with some pliers or wire cutters. This will also help keep it in place when you use the epoxy. Be sure it’s Marine-Tex (available at decent boat suppy).
Or you could buy a new carb.
Keep that fire bottle ready. I hope everyone that drives these kit cars keeps at least one fresh bottle in the car.