You can watch it fall over at 0:34 in.
So during a private shareholder's thing a few weeks ago, Chairman of Parks and Experiences Josh D'Amaro may have whipped out a real lightsabre, but that was shrouded in secrecy, so here, have the walking robot they made instead.
From Tech Crunch:
“Project KIWI started about three years ago to figure out how we can bring our smaller characters to life at their actual scale in authentic ways,” Scott LaValley says. “It’s an exciting time for bipedal robotics and with an incredible team and our combination of technology, artistry, and magic, we are bringing characters to life that could not have happened anywhere but Disney.”