fix(ComboBox): preserve input on blur and toggle

[adamalston]

Closes #20370

Preserved ComboBox input on blur and toggle.

Changelog

New

• Added ComboBox tests.

Changed

• Preserved ComboBox input on blur and toggle.

Testing / Reviewing

After reverting the code change, all added or updated tests should fail.

This fix appears to address a regression introduced in #18544. It’s unclear whether #18484, which that pull request was intended to address, should be re-evaluated.

PR Checklist

As the author of this PR, before marking ready for review, confirm you:

• Reviewed every line of the diff
• Updated documentation and storybook examples
• Wrote passing tests that cover this change
• Addressed any impact on accessibility (a11y)
• Tested for cross-browser consistency
• Validated that this code is ready for review and status checks should pass

More details can be found in the pull request guide

[codecov]

Codecov Report

❌ Patch coverage is 75.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 91.74%. Comparing base (30b4f87) to head (50f61d0).
⚠️ Report is 128 commits behind head on main.

Files with missing lines	Patch %	Lines
...ackages/react/src/components/ComboBox/ComboBox.tsx	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #20405      +/-   ##
==========================================
+ Coverage   91.39%   91.74%   +0.34%     
==========================================
  Files         485      482       -3     
  Lines       31370    32218     +848     
  Branches     5430     5506      +76     
==========================================
+ Hits        28670    29557     +887     
+ Misses       2547     2509      -38     
+ Partials      153      152       -1     

Flag	Coverage Δ
main-packages	84.92% <75.00%> (-0.02%)	⬇️
web-components	97.31% <ø> (+0.15%)	⬆️

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[maradwan26]

This fixes the issue with the value being cleared when closing with the chevron but now the previously resolved issue #18484 has resurfaced

Screen.Recording.2025-09-04.at.11.54.42.AM.mov