I personally wouldn't jump a baby that high that young. I don't think it would hurt every once in a while over really low stuff. But a baby is growing, and that impact on their front legs is not good for them at that young of an age.
I'm not a jumper, but with all the videos up that show foals jumping, it looks somewhat common. But I will say on the video you posted, that jump looks way too high for a foal. I think if you were going to do that at all (which I probably wouldn't reccommend) I would start at a lower height like this video.