Setting late attribute's value through non type-safe metamodel causes NPE

[fill0llif]

Setting late attribute's value through non type-safe metamodel causes NPE.

shared class Type() {
	shared late String attr;
}
shared void run() {
	`value Type.attr`.memberSet(Type(), "test");
}

As shown also in #7443, it seems 'Type.attr' is actually an Attribute<Type,String,Nothing>, but it should be an Attribute<Type,String,String>.