feat: Removes the Multiple Line Charts

[michael-s-molina]

SUMMARY

This PR removes the Multiple Line Charts.

• Removes the legacy chart code and unregisters the plugin.
• Removes old plugin references throughout the codebase
• Updates unit tests
• Updates E2E tests
• Updates the example dashboards
• Updates translation files

The Multiple Line Charts description says that it's deprecated and people should use the Mixed chart instead. The problem is that Multiple Line Charts allows you to select 2 charts which may reference different datasets while Mixed Chart only allows 1 dataset. This means that to compare values from different datasets using a Mixed chart you would need to create another dataset combining the source datasets. Given that this chart is marked as deprecated for a long time, a migration would required significant effort, and its adoption is pretty low, we decided to remove it. If someone still has this chart and tries to access it, the following screen will be displayed:

AFTER SCREENSHOT

TESTING INSTRUCTIONS

1 - Make sure all Multiple Line Charts were removed
2 - Make sure Multiple Line Charts is not available anymore in the viz picker

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[codecov]

Codecov Report

Merging #23933 (31cb15b) into master (f5148ef) will increase coverage by 0.68%.
The diff coverage is 0.00%.

❗ Current head 31cb15b differs from pull request most recent head 6cdcd20. Consider uploading reports for the commit 6cdcd20 to get more accurate results

@@            Coverage Diff             @@
##           master   #23933      +/-   ##
==========================================
+ Coverage   67.84%   68.53%   +0.68%     
==========================================
  Files        1944     1941       -3     
  Lines       75328    75221     -107     
  Branches     8218     8216       -2     
==========================================
+ Hits        51110    51554     +444     
+ Misses      22107    21555     -552     
- Partials     2111     2112       +1     

Flag	Coverage Δ
hive	53.60% <ø> (+0.06%)	⬆️
javascript	54.96% <0.00%> (+0.05%)	⬆️
mysql	79.22% <ø> (?)
presto	53.52% <ø> (+0.06%)	⬆️
python	83.03% <ø> (+1.37%)	⬆️
sqlite	?
unit	53.95% <ø> (+0.06%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...nd/plugins/legacy-preset-chart-nvd3/src/NVD3Vis.js	0.00% <0.00%> (ø)
...end/plugins/legacy-preset-chart-nvd3/src/preset.js	0.00% <ø> (ø)
...dashboard/components/AddSliceCard/AddSliceCard.tsx	63.63% <0.00%> (-2.28%)	⬇️
...ponents/controls/VizTypeControl/VizTypeGallery.tsx	88.23% <ø> (ø)
...-frontend/src/visualizations/presets/MainPreset.js	100.00% <ø> (ø)
superset/charts/schemas.py	99.37% <ø> (ø)
superset/cli/examples.py	0.00% <ø> (ø)
superset/examples/data_loading.py	0.00% <ø> (ø)
superset/viz.py	65.14% <ø> (+1.24%)	⬆️

... and 39 files with indirect coverage changes

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[john-bodley]

@michael-s-molina from a UX perspective if a user is presented with this message there's no real clear way forward, i.e., they're not able to see what the legacy chart looks like and thus can't easily recreate it in a different form.

Rather than simply deleting the chart type, would it be preferable to provide a toast which states that this chart type is deprecated and will be removed in Superset 4.0. Additionally the toast should mention that the chart must be manually migrated.

[michael-s-molina]

Rather than simply deleting the chart type, would it be preferable to provide a toast which states that this chart type is deprecated and will be removed in Superset 4.0. Additionally the toast should mention that the chart must be manually migrated.

@john-bodley This chart type was marked as deprecated in a previous major version and people had more than a year to migrate from it. It's related to a 2.0 -> 3.0 cycle as opposed to 3.0 -> 4.0.