Wrong order for bar chart sorting with null values

[oshikryu]

When data has null values, sort them to the end (if descending) and beginning (if ascending)

Example of improper sorting.

https://codepen.io/oshikryu/pen/MWaJgLx

This is the simple case where there is no bar grouping value.
The issue with the bar grouping value is here: #4749

[alexcjohnson]

Fixed by #4783 🎉