Make the InitNavigationControl() public again

A while ago, a lot of Navigation System code has been moved to its own Navigation System Module…

As for InitNavigationControl(AController& Controller)… It used to be Public, then become DEPRECATED, and now is inside Anonymous Namespace in the AIBlueprintHelperLibrary.cpp file.

You can move that function wherever you want, just… can you make it Public again please?

Thank You.