Editor: Fixed TODO: Bind lexical this

[ycw]

This PR fixed a TODO in ui.three.js about binding this without .bind(); this.update is consumed here:

UIPoints2

three.js/editor/js/libs/ui.three.js

Lines 683 to 684 in db0a63d

	const txtX = new UINumber( x ).setWidth( '30px' ).onChange( this.update );
	const txtY = new UINumber( y ).setWidth( '30px' ).onChange( this.update );

UIPoints3

three.js/editor/js/libs/ui.three.js

Lines 778 to 780 in db0a63d

	const txtX = new UINumber( x ).setWidth( '30px' ).onChange( this.update );
	const txtY = new UINumber( y ).setWidth( '30px' ).onChange( this.update );
	const txtZ = new UINumber( z ).setWidth( '30px' ).onChange( this.update );