Allow breathmasks to be fitted into other masks

[Dr_Bee]

Many masks are novelties not intended to be worn, and horse masks, clown masks, and facehuggers (can't get them anymore) already act as internals if worn, seriously, its hilarious but it works.

I know for a fact that the clown mask doesnt act as internals on gooncode. it does on other codebases. it is sad because It means a clown has to choose between the eternal shame of taking off his face or precious life giving oxygen.