SetNPCBlackboard() changed behavior when passing nil

In order to allow unsetting blackboard variables, the behavior when calling SetNPCBlackboard(entity, variable, nil) was changed. Before 4.10 Beta 5 this was a noop change. As of 4.10 Beta 5 the call will now clear the variable. See XRUIMOD-138 - Getting issue details... STATUS for details.

We don't expect any issues out of this, since we assume that anybody actually calling the function that way expected the value to be reset. Feel free to leave us a comment here, if that behavior change causes problems for you.