Node connect points with nullable types should have 50% alpha

[Nytra]

This would make them match default Neos behavior. LogixHelper returns a color with 50% alpha (0.4 alpha, as opposed to 0.8) for any nullable type. You can test this by using the pack/unpack nullable nodes and looking at the color of the wires and connect points.

[Banane9]

I've specifically done 100% alpha, as otherwise the node's border would show through the connect points.

I'll do the same thing as with the regular connectors though and "calculate in" the effect.