Update to mediapipe facemesh about facemeshfacegeometry

[jthawme]

I wouldn't feel confident enough for a PR on this, but to drop some further information, it looks very similar in a lot of ways, but the results from the facemesh library linked above come in like

function onResults(results) {
  const {multiFaceLandmarks} = results;
  
  // [
  //   ...468 items
  //   { x: 0.4, y: 0.6, z: -0.1 }
  // ]
}

They're all values from 0-1, except z I believe

Atm i am exploring using it by doing

geo.update({
  scaledMesh: multiFaceLandmarks[0].map(vec => Object.values(vec))
})

But its not 100% correct yet, but works without erroring and does create a mesh