Fix avoid-overlap hover label algo when "too close" label get filtered out

[etpinard]

fixes #3603

before: https://codepen.io/antoinerg/pen/MxEjeo

after: https://codepen.io/etpinard/pen/LaBpYm

In this example, we enter this block:

plotly.js/src/components/fx/hover.js

Lines 872 to 877 in fc236e2

	// remove the "close but not quite" points
	// because of error bars, only take up to a space
	hoverData = hoverData.filter(function(d) {
	return (d.zLabelVal !== undefined) ||
	(d[commonAttr] || '').split(' ')[0] === t00;
	});

where hoverData gets filtered down showing two visible hover labels, but isn't updated for the downstream hoverAvoidOverlaps call where the "old" (longer) hoverData array is used here:

plotly.js/src/components/fx/hover.js

Lines 1099 to 1114 in fc236e2

	var pointgroups = hoverData.map(function(d, i) {
	var axis = d[ax];
	var axIsX = axis._id.charAt(0) === 'x';
	var rng = axis.range;
	if(!i && rng && ((rng[0] > rng[1]) !== axIsX)) axSign = -1;
	return [{
	i: i,
	traceIndex: d.trace.index,
	dp: 0,
	pos: d.pos,
	posref: d.posref,
	size: d.by * (axIsX ? YFACTOR : 1) / 2,
	pmin: 0,
	pmax: (axIsX ? fullLayout.width : fullLayout.height)
	}];
	})

cc @plotly/plotly_js

[antoinerg]

Thank you for the fix @etpinard ! It looks good to me 💃