fix(nested-tab-available): make the another tabs into one tabs available

[prosdev0107]

SUMMARY

Unable to add Tabs inside a Tab unless the Tab already has other elements (Dashboard Layout)

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

Before:

After:

TESTING INSTRUCTIONS

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 #18877 (bd0f26b) into master (c8df849) will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #18877      +/-   ##
==========================================
+ Coverage   66.31%   66.32%   +0.01%     
==========================================
  Files        1620     1634      +14     
  Lines       63075    63315     +240     
  Branches     6370     6428      +58     
==========================================
+ Hits        41827    41994     +167     
- Misses      19591    19641      +50     
- Partials     1657     1680      +23     

Flag	Coverage Δ
javascript	51.38% <ø> (+0.13%)	⬆️

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

Impacted Files	Coverage Δ
...set-frontend/src/dashboard/util/getDropPosition.js	88.67% <ø> (+1.40%)	⬆️
superset-frontend/src/dataMask/actions.ts	54.54% <0.00%> (-18.19%)	⬇️
...acy-preset-chart-deckgl/src/utilities/controls.jsx	11.11% <0.00%> (-8.89%)	⬇️
...perset-frontend/src/views/components/MenuRight.tsx	72.13% <0.00%> (-8.36%)	⬇️
superset-frontend/src/dataMask/reducer.ts	43.33% <0.00%> (-6.67%)	⬇️
...board/components/nativeFilters/FilterBar/index.tsx	64.22% <0.00%> (-5.60%)	⬇️
...-frontend/src/components/AlteredSliceTag/index.jsx	87.69% <0.00%> (-2.64%)	⬇️
...d/components/DashboardBuilder/DashboardBuilder.tsx	72.72% <0.00%> (-2.57%)	⬇️
...rset-frontend/src/explore/components/SaveModal.tsx	63.63% <0.00%> (-2.50%)	⬇️
superset-frontend/src/components/Select/Select.tsx	86.69% <0.00%> (-0.67%)	⬇️
... and 83 more

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[rusackas]

/testenv up

[github-actions]

@rusackas Ephemeral environment spinning up at http://52.40.162.64:8080. Credentials are admin/admin. Please allow several minutes for bootstrapping and startup.

[rusackas]

Just delete the code (and the TODO) rather than commenting it out.

Also adding @williaster as a reviewer... he wrote this original check, so I'm not sure if there's rationale for the prevention of nested tabs that we'd want to preserve.

[rusackas]

Pinging @graceguo-supercat for any additional historical context on why we have this limitation, in case @williaster is unavailable.

[github-actions]

Ephemeral environment shutdown and build artifacts deleted.