Position-editable horizontal legend toggle fixups

[etpinard]

fixes #2819, an edge case that made

plotly.js/src/components/legend/draw.js

Lines 343 to 354 in 0426b61

	clickFn: function(numClicks, e) {
	var clickedTrace = fullLayout._infolayer.selectAll('g.traces').filter(function() {
	var bbox = this.getBoundingClientRect();
	return (
	e.clientX >= bbox.left && e.clientX <= bbox.right &&
	e.clientY >= bbox.top && e.clientY <= bbox.bottom
	);
	});
	if(clickedTrace.size() > 0) {
	clickOrDoubleClick(gd, legend, clickedTrace, numClicks, e);
	}
	}

not grab the correct legend item bounding boxes when edits.legendPosition was turned on.

cc @alexcjohnson

[alexcjohnson]

Beautiful. Thanks for sorting out that flakiness. 💃