fix(plugin-chart-table): refine ordering logic

[villebro]

🐛 Bug Fix
Previously table chart would by default order by the first metric if no sort order was specified. This replicates the logic from the old viz.py implementation and also fixes a few minor issues in the current code:

• Infer queryMode from formData contents; if it's undefined and metrics is not empty, assume QueryMode.aggregate. This is the case in some old metadata, e.g. the World Bank example dashboard.
• timeseries_limit_metric is [] when the control is unset, and QueryFormMetric when set. The type is updated and a util is added for normalizing to QueryFormMetric[] + relevant tests.
• Added a missing license header.

AFTER

BEFORE

[vercel]

This pull request is being automatically deployed with Vercel (learn more).
To see the status of your deployment, click below or on the icon next to each commit.

🔍 Inspect: https://vercel.com/superset/superset-ui/k57lswnpy
✅ Preview: https://superset-ui-git-fork-preset-io-villebro-fix-table-orderby.superset.now.sh

[villebro]

In practice timeseriesLimitMetric is always truthy, as the control always returns either an empty array (nothing selected) or a string/object (=an orderby is set). See the updated type in types.ts.

[ktmud]

Wow, didn't notice the control returns an empty array when nothing is selected. That sounds wrong.

[codecov]

Codecov Report

Merging #930 (068d6cf) into master (84f8e45) will increase coverage by 0.04%.
The diff coverage is 57.14%.

@@            Coverage Diff             @@
##           master     #930      +/-   ##
==========================================
+ Coverage   27.32%   27.37%   +0.04%     
==========================================
  Files         411      412       +1     
  Lines        8281     8292      +11     
  Branches     1134     1139       +5     
==========================================
+ Hits         2263     2270       +7     
- Misses       5886     5888       +2     
- Partials      132      134       +2     

Impacted Files	Coverage Δ
plugins/plugin-chart-table/src/buildQuery.ts	68.42% <33.33%> (-16.20%)	⬇️
...ins/plugin-chart-table/src/utils/extractOrderby.ts	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 84f8e45...068d6cf. Read the comment docs.

[ktmud]

LGTM. Thanks for the fix!