fix: Intenral container without content has incorrect border radius

[YueyingLu]

Description

Follow up fix of #663 to apply fix for internal & external use cases.

Related links, issue #, if available: n/a

How has this been tested?

Review checklist

The following items are to be evaluated by the author(s) and the reviewer(s).

Correctness

• Changes include appropriate documentation updates.
• Changes are backward-compatible if not indicated, see CONTRIBUTING.md.
• Changes do not include unsupported browser features, see CONTRIBUTING.md.
• Changes were manually tested for accessibility, see accessibility guidelines.

Security

• If the code handles URLs: all URLs are validated through the checkSafeUrl function.

Testing

• Changes are covered with new/existing unit tests?
• Changes are covered with new/existing integration tests?

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[codecov]

Codecov Report

Base: 92.98% // Head: 92.98% // Increases project coverage by +0.00% 🎉

Coverage data is based on head (3dfef79) compared to base (090a87d).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #669   +/-   ##
=======================================
  Coverage   92.98%   92.98%           
=======================================
  Files         574      574           
  Lines       16781    16782    +1     
  Branches     4631     4632    +1     
=======================================
+ Hits        15603    15604    +1     
  Misses       1101     1101           
  Partials       77       77           

Impacted Files	Coverage Δ
src/container/index.tsx	100.00% <ø> (ø)
src/container/internal.tsx	95.74% <100.00%> (+0.09%)	⬆️

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