fix: prevent React crash on single-child table headers #2256

[h30s]

What kind of change does this PR introduce?
Bugfix

Issue Number:

• Closes 🐛 Bug: React rendering crash in StyledMarkdownBlock for single-child table headers #2256

Screenshots/videos:
N/A

If relevant, did you update the documentation?
No

Summary
This PR resolves a page crash that happens when rendering single-column Markdown tables. The checkHasContent utility was assuming reactNode.props.children is always an array and calling .reduce(). However, React provides a single object when there's only one child. I wrapped the children with React.Children.toArray() to safely normalize before iterating. Also added a Cypress component test to catch regressions.

Does this PR introduce a breaking change?
No

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read, understood, and followed the contributing guidelines.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (2ee67ff) to head (503b444).

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #2261   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files           30        30           
  Lines          663       663           
  Branches       205       205           
=========================================
  Hits           663       663           

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[h30s]

Hi @Utkarsh-123github, @jagpreetrahi, and @vtushar06 requesting your kind review on this PR at your convenience.