fix: Add I18nProvider support for code editor theme filtering input

[avinashbot]

Description

What it says on the tin. We missed those strings earlier, adding support for them now.

Related links, issue #, if available: AWSUI-60202

How has this been tested?

Updated unit tests.

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 96.44%. Comparing base (35a2b2a) to head (d5c51fa).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff            @@
##             main    #3265    +/-   ##
========================================
  Coverage   96.44%   96.44%            
========================================
  Files         791      791            
  Lines       22567    22567            
  Branches     7384     7800   +416     
========================================
  Hits        21764    21764            
+ Misses        796      750    -46     
- Partials        7       53    +46     

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