Excalidraw: Remove uncommitted point when alt is lifted

[xixixao]

This is for editing linear elements. When you press alt and move cursor a new point is added.

Right now this "uncommitted" point is removed after alt key is released and cursor is moved.

I think we should remove the point straight away after the key is released. This will make the interaction feel snappier.

[dwelle]

Agreed. Already mentioned in the umbrella