Describe the issue
In a cartesian chart, if two data points fall into the same position, the topmost highlighter covers the bottom most.
The problem is that the topmost highlighter is not the one relative to the topmost geometry, but the opposite.
If you check the attached screenshot you can see that:

• Sensor1, in green, is rendered in the background of Sensor 2, in blue.
• Sensor1 is shown on the top in the Legend and in the tooltip.
• Sensor1 highlighter is shown on top of the Sensor2 highlighter.

the Y data for the two series is:

green: [1, 0.8, 0.5, 0.2]
blue: [1, 0.8, 0.76, 0.12]

Expected behaviour
The rendering order of the highlighter should follow the rendering order of the geometries.

Additional context
A test case was added in #1922