fix(explore): metric label disappearing in some scenarios

[kgabryje]

SUMMARY

When user added an adhoc metric, then opened a popover to edit that metric and clicked "Save" without doing any changes, the metric label would disappear. This PR adds a check if old and edited metric are equal - if they are, no actions are taken.

Basically what happened was that when we saved a metric without any changes, we didn't call coerceAdhocMetrics (which converts an object to AdhocMetric), but we did call onChange. The result was that we passed a normal object instead of AdhocMetric instance to value renderer, and in value renderer we checked for instanceof AdhocMetric

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

Before: see linked issue
After:
https://user-images.githubusercontent.com/15073128/129003100-1701671f-b658-49ad-bb2e-3ed13c0e5207.mov

TESTING INSTRUCTIONS

0. Enable dnd
1. Create a chart and add an adhoc metric
2. Open a popover to edit that metric and click save without doing any changes
3. The metric label should stay as it was, no changes should happen

ADDITIONAL INFORMATION

• Has associated issue: fixes [dnd][explore] Metric filed will shrink when change aggregate function with a changed metric label #16184
• 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

CC @jinghua-qa @junlincc

[codecov]

Codecov Report

Merging #16190 (0885ebb) into master (4df3672) will decrease coverage by 0.00%.
The diff coverage is 0.00%.

❗ Current head 0885ebb differs from pull request most recent head b8345d6. Consider uploading reports for the commit b8345d6 to get more accurate results

@@            Coverage Diff             @@
##           master   #16190      +/-   ##
==========================================
- Coverage   76.83%   76.82%   -0.01%     
==========================================
  Files         996      996              
  Lines       53060    53062       +2     
  Branches     6766     6767       +1     
==========================================
  Hits        40766    40766              
- Misses      12066    12068       +2     
  Partials      228      228              

Flag	Coverage Δ
javascript	71.16% <0.00%> (-0.01%)	⬇️

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Impacted Files	Coverage Δ
...ontrols/DndColumnSelectControl/DndMetricSelect.tsx	41.21% <0.00%> (-0.57%)	⬇️

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[kgabryje]

/testenv up FEATURE_ENABLE_EXPLORE_DRAG_AND_DROP=true

[github-actions]

@kgabryje Ephemeral environment spinning up at http://35.155.136.177:8080. Credentials are admin/admin. Please allow several minutes for bootstrapping and startup.

[villebro]

LGTM and tested to work well!

[github-actions]

Ephemeral environment shutdown and build artifacts deleted.

[rosemarie-chiu]

🏷 2021.31