fix(event): Fix interaction with viewBox

[netil]

Issue

#3414

Details

Fix basic interaction when scale is update with viewBox

// generation option used
bb.generate({
	size: {
		width: 320,
		height: 240
	},
	resize: { auto: false },
	data: {
		columns: [
			["data1", 300, 350, 300, 0, 0, 0],
			["data2", 130, 100, 140, 200, 150, 50]
		],
		type: "line"
	},
	onrendered() {
		this.$.svg
			.attr("viewBox", "0 0 320 240")
			.style("width", "100%")
			.style("height", "auto");
	}
});

[coveralls]

coverage: 94.245% (-0.02%) from 94.263%
when pulling a163358 on netil:viewBox#3414
into e32ba57 on naver:master.