Input selection sample does weird things if you have multiple none handed inputs

[AdaRoseCannon]

https://github.com/immersive-web/webxr-samples/blob/main/input-selection.html

This pattern seems to cause the problem.

let i = (ev.inputSource.handedness == "left") ? 0 : 1;
currently_selected_boxes[i] = box;
box.scale = [1.25, 1.25, 1.25];
box.selected = false;