Derivation of conservation of angular momentum

I read a derivation of conservation of angular momentum. The derivation used strong form of newtons third law. This was the derivation

It was written after derivation that lorentz force does not follow strong form of newtons third law but angular momentum is still conserved because it is stored in electromagnetic field. I think friction also does not follow strong form of newton's third law so how is angular momentum conserved in presence of frictional force?