Mixed Chart - enable X-AXIS SORT BY

[jpdeloitte]

Bug description

Currently you are unable to sort the X-Axis of a mixed chart based on a metric value (from either Query A or Query B). The chart is sorted alphabetically by the X-Axis dimension value. Other echarts (e.g. Bar Chart) have this capability built in already, and this needs to be added to the Mixed Chart.

Screenshots/recordings

Bar Chart

Mixed Chart

Superset version

master / latest-dev

Python version

3.9

Node version

16

Browser

Chrome

Additional context

No response

Checklist

• I have searched Superset docs and Slack and didn't find a solution to my problem.
• I have searched the GitHub issue tracker and didn't find a similar bug report.
• I have checked Superset's logs for errors and if I found a relevant Python stacktrace, I included it here as text in the "additional context" section.

[rusackas]

We'd most certainly welcome a PR adding this functionality if you (or anyone reading this) are so inclined! Meanwhile I'll convert this to an "Ideas" discussion, since it's more feature request than bug.

[rusackas]

Well... it seems "convert to issue" is busted on GitHub at the moment. Perhaps another day!