Mirrored axes have a huge bounding box

[nicolaskruchten]

setting mirror: 'allticks' on an axis results in a giant bounding box for the axis, which causes problems with the new automargin flag on axes, and the positioning of the rangeslider. You can see this problem in action by setting automargin on any of the axes here (once we release 1.35.0) https://codepen.io/nicolaskruchten/pen/WMWvVz

This is due to the fact that the mirrored axis is drawn with the same path as the 'main' axis where the ticklabels are. It would make some sense to draw that secondary axis in a different element, so that the bounding box of the main axis is independent of the mirror attribute.

[alexcjohnson]

Really what we need to do is get rid of the getBoundingClientRect calls there altogether. This causes all sorts of problems, see #1988