Fix getting labels from C++

[Islandman93]

Currently there's no way to get the labels from C++ to Julia & I have been unable to get something like this to work:

.method("labels", [](GameState &gs) { 
     return jlcxx::ArrayRef<Label, 1>(labels.data(), labels.size()); 
});

I've tried Label*, & other variations. As far as I can tell from https://discourse.julialang.org/t/passing-an-array-of-a-c-class-to-julia-cxxwrap/17622 this doesn't seem possible.