Fix mouse targeting for targets behind character

[srmalloy]

It has been an ongoing issue all the way back to Live; is there some way to prevent a targetable object that is behind your character and outside the view of your camera from being made the default interaction object? What is happening is that, for example, with a character that has a pet of some kind comes up to one of the sliding doors in a mission and brings their mouse pointer up to click on the door with their pet behind them and not drawn in the camera view because it's outside of the field of view, the mouse pointer will turn red so that clicking the mouse targets the pet; you have to play camera angle games to get a view that doesn't have the pet's targeting box occlude the object you're trying to click on. And it doesn't have to be a pet; I've had occasions where I've tried to click on a hostile mob in front of me, but the mob that clicking targets is one standing behind me that I can't even see. The 'targeting box' for objects appears to be larger than the drawing size for the objects, so that even if they aren't big enough to be visible behind you, their targeting box is still in the camera field of view, and preempt more distant objects.