This function is useful in case the prim is inside a variant set: In that case, just calling FUsdStage::RemovePrim() will attempt to remove the "/Root/Example/Child", which wouldn't remove the "/Root{Varset=Var}Example/Child" spec, meaning the prim may still be left on the stage. Note that it's even possible to have both of those specs at the same time: for example when we have a prim inside a variant set, but outside of it we have overrides to the same prim. This function will remove both.