Of course Tesla can void your warranty. If the screen stopped working or anything to do with the screen malfunctioning - happened, they could easily blame it on the modification. Now, of course you could put the screen back to how it was before bringing the car in, but if you brought the car in with a screen issue - mounted like that, I can almost guarantee Tesla won't cover it.
Again, look at the video, it's one plug, one plug. How can you screw up one plug to void your warranty?