Excess Padding in Horizontal Bar Charts When Legend is Added

[seandiacono]

Bug description

Horizontal bar charts in Apache Superset are created with extra padding when a legend is added, affecting the chart's layout and appearance. This issue was introduced in PR #27883.

Expected Behavior:
The chart should adjust the layout to accommodate the legend without adding excessive padding.

How to reproduce the bug

1. Create a horizontal bar chart
2. Ensure that the legend is enabled and the margin is set to 0 or none
3. You should see extra padding between the chart and the legend

Screenshots/recordings

Superset version

4.0.1

Python version

3.9

Node version

16

Browser

Chrome

Additional context

This bug was validated by @sfirke in Slack

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.

[sfirke]

This caused existing charts to display differently on dashboards upon upgrading from 4.0.0. The temporary fix is to set legend margin in chart to -100, but that would require modifying every affected chart -- then presumably undoing it once the bug is fixed.