fix(Explore): Pivot table V2 sort by failure with D&D enabled

[geido]

SUMMARY

This PR fixes an issue for which the Pivot Table V2 would fail when the "Sort by" control was cleared with D&D enabled.
The reason for the failure was that when the "Sort by" was cleared, the series_limit_metric was passed as an empty array due to the default behavior of the Select control.
With the changes in this PR, the series_limit_metric type is strictly checked and converted to undefined when the selection is cleared up / an empty array is passed.

BEFORE

DEV.Video.Game.Sales.Pivot.Table.V2.mp4

AFTER

DEV.Video.Game.Sales.Pivot.Table.V2.1.mp4

TESTING INSTRUCTIONS

1. Open a Pivot Table V2 with D&D enabled
2. Add a "Sort by" option
3. Clear the "Sort by"
4. Make sure the data is loaded as expected

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags: ENABLE_EXPLORE_DRAG_AND_DROP ENABLE_DND_WITH_CLICK_UX
• 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 #18835 (6e72937) into master (c491829) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master   #18835   +/-   ##
=======================================
  Coverage   66.36%   66.37%           
=======================================
  Files        1620     1620           
  Lines       63041    63046    +5     
  Branches     6375     6376    +1     
=======================================
+ Hits        41839    41844    +5     
  Misses      19543    19543           
  Partials     1659     1659           

Flag	Coverage Δ
javascript	51.26% <100.00%> (+<0.01%)	⬆️

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

Impacted Files	Coverage Δ
...ges/superset-ui-core/src/query/buildQueryObject.ts	100.00% <100.00%> (ø)
...ackages/superset-ui-core/src/query/types/Column.ts	100.00% <100.00%> (ø)
...mponents/controls/AnnotationLayerControl/index.jsx	10.16% <0.00%> (ø)

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[kgabryje]

Tested, works perfectly!