chore: Add built-in internationalization to button dropdown filtering

[avinashbot]

Description

The translations were around for a while, just forgot to integrate it into the components.

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

How has this been tested?

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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[Copilot]

Pull request overview

Adds internal i18n support for ButtonDropdown filtering-related strings by wiring the component to useInternalI18n and introducing new message keys across the supported locales.

Changes:

• Introduces new button-dropdown message keys (filteringResultsText, noMatch, and i18nStrings.filteringItemAriaDescription) across locale catalogs.
• Updates ButtonDropdown to resolve filteringResultsText and filteringItemAriaDescription via the internal i18n hook.
• Adds unit tests validating i18n-provider fallback vs prop override behavior for the new strings.

Reviewed changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/i18n/messages/all.en.json	Adds button-dropdown i18n strings (EN).
src/i18n/messages/all.en-GB.json	Adds button-dropdown i18n strings (EN-GB).
src/i18n/messages/all.de.json	Adds button-dropdown i18n strings (DE).
src/i18n/messages/all.es.json	Adds button-dropdown i18n strings (ES).
src/i18n/messages/all.fr.json	Adds button-dropdown i18n strings (FR).
src/i18n/messages/all.it.json	Adds button-dropdown i18n strings (IT).
src/i18n/messages/all.pt-BR.json	Adds button-dropdown i18n strings (PT-BR).
src/i18n/messages/all.tr.json	Adds button-dropdown i18n strings (TR).
src/i18n/messages/all.id.json	Adds button-dropdown i18n strings (ID).
src/i18n/messages/all.ko.json	Adds button-dropdown i18n strings (KO).
src/i18n/messages/all.ja.json	Adds button-dropdown i18n strings (JA).
src/i18n/messages/all.zh-CN.json	Adds button-dropdown i18n strings (ZH-CN).
src/i18n/messages/all.zh-TW.json	Adds button-dropdown i18n strings (ZH-TW).
src/i18n/messages/all.ar.json	Adds button-dropdown i18n strings (AR).
src/i18n/messages-types.ts	Adds button-dropdown namespace typing for new message keys/format args.
src/button-dropdown/index.tsx	Resolves filtering strings through useInternalI18n.
src/button-dropdown/tests/button-dropdown-i18n.test.tsx	Adds tests for i18n-provider fallback and prop precedence.

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[avinashbot]

Fine for now; thinking about having the string accept a react node as fallback but that can come in a different PR.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.64%. Comparing base (523ea64) to head (71dbaad).
⚠️ Report is 13 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4884   +/-   ##
=======================================
  Coverage   97.64%   97.64%           
=======================================
  Files         958      958           
  Lines       31238    31250   +12     
  Branches    11530    11537    +7     
=======================================
+ Hits        30501    30513   +12     
- Misses        690      730   +40     
+ Partials       47        7   -40     

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