feat: add standalone content display preference component

[ernst-dev]

Description

Exposes the content-display preference control (drag-and-drop column reordering + visibility toggles, optional column filtering and grouping) as a standalone ContentDisplayPreference component, usable outside the CollectionPreferences modal.

Unlike CollectionPreferences, the standalone component is fully controlled and emits an onChange event immediately on every reorder/toggle (no confirm step). This lets consumers react to selection before submission — e.g. enforce a maximum number of visible columns, which is the motivating use case in the linked request.

The implementation reuses the existing internal content-display renderer (src/collection-preferences/content-display) rather than duplicating it. CollectionPreferences continues to render the same shared core unchanged, so its behavior and public API are unaffected.

Changes:

• New public component src/content-display-preference/ (index.tsx, internal.tsx, interfaces.ts, styles.scss). ContentDisplayPreferenceProps reuses the shared content-display item/option/i18n types from CollectionPreferencesProps to stay in sync.
• Test-utils DOM wrapper (src/test-utils/dom/content-display-preference) extending the existing content-display wrapper.
• Pluralization entry for the new component name (build-tools/utils/pluralize.js).
• Unit tests and a dev page (pages/content-display-preference/simple.page.tsx) demonstrating the "max visible columns" reactive use case.

Related links, issue #, if available: AWSUI-60078

How has this been tested?

• npm run quick-build — green.
• eslint + stylelint on the new/changed files — green.
• New unit tests (13, incl. rendering, immediate onChange on toggle & keyboard reorder, alwaysVisible, column filtering, groups, and base-component API) — all pass.
• Existing collection-preferences/content-display unit tests (56) — still pass (shared core untouched).

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?

---

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.