fix: Flashbar context for key-value pairs and popover

[pan-kot]

Description

The flashbar visual context does not have support for a number of common Cloudscape components, including certain variants of text, buttons, key-value pairs, popover.

Before:

Screen.Recording.2025-12-08.at.16.44.57.mov

After:

Screen.Recording.2025-12-09.at.12.09.19.mov

Rel: [AWSUI-61549]

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

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.12%. Comparing base (5f1e362) to head (a388bf4).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4096   +/-   ##
=======================================
  Coverage   97.12%   97.12%           
=======================================
  Files         864      864           
  Lines       25327    25328    +1     
  Branches     9141     9141           
=======================================
+ Hits        24599    24600    +1     
- Misses        681      722   +41     
+ Partials       47        6   -41     

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