Regression - Echarts Bar and Line chart label values changed unexpectectly when using Group By

[cwegener]

After #19116, the label values for Echarts Bar and Line chart (possibly more, but those are the only ones I noticed) have changed on charts that use a Group By field.

How to reproduce the bug

1. Install Superset from commit 375c03e
2. Load example dataset
3. Create a new Echarts bar chart (i.e. Time-Series Bar Chart v2) using any example dataset (e.g. cleaned_sales_data)
4. Pick a metric for the new chart (e.g. SUM(sales))
5. Pick a "Group By" field for the new chart (e.g. status)
6. Observe the chart labels. This is the easiest when showing the Legend.

Expected results

The chart label values will be the values from the "Group By" field

Actual results

The chart label values are a concatenation ("flattened") the metric key (i.e. SUM(sales) in my example) + ", " + the value from the "Group By" field

Screenshots

Behaviour at git checkout 375c03e08:

Behaviour at git checkout 375c03e08~:

Environment

(please complete the following information):

• browser type and version: Firefox 99
• superset version: git checkout 375c03e08
• python version: Python 3.10.4
• node.js version: Node v16.9.1
• any feature flags active: Default

Checklist

Make sure to follow these steps before submitting your issue - thank you!

• I have checked the superset logs for python stacktraces and included it here as text if there are any.
• I have reproduced the issue with at least the latest released version of superset.
• I have checked the issue tracker for the same issue and I haven't found one similar.

Additional context

NVD3 charts do not appear to exhibit this regression.

[zhaoyongjie]

This issue was fixed by #19716, so closed.