feat: Add custom item renderer for button dropdown

[SpyZzey]

Description

This pull request introduces support for custom rendering of dropdown items in the ButtonDropdown component by adding a new renderItem prop. This allows consumers to provide a custom function to render dropdown options, including group headers and checkboxes, for both desktop and mobile variants. The implementation ensures that custom content replaces the default rendering and removes styling.

Related links, issue #, if available: [ZgQTAB1aCSIF], [aFSEAgRVeHSz], [D349419275]

How has this been tested?

• Manual testing
• Unit testing

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 97.16%. Comparing base (e7feb35) to head (c55aec4).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4156   +/-   ##
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  Coverage   97.16%   97.16%           
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  Files         879      879           
  Lines       25749    25780   +31     
  Branches     9303     9328   +25     
=======================================
+ Hits        25018    25049   +31     
  Misses        725      725           
  Partials        6        6           

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[Copilot]

Pull request overview

This pull request adds custom rendering support for dropdown items in the ButtonDropdown component through a new renderItem prop. This feature allows consumers to provide custom render functions for all item types (actions, checkboxes, and groups), supporting both desktop and mobile variants.

Changes:

• Added renderItem prop to ButtonDropdown component with comprehensive TypeScript type definitions for different item types
• Implemented prop threading through the component hierarchy to support custom rendering at all levels
• Added no-content-styling CSS classes to remove default styling when custom rendering is used
• Added index prop to track item positions for custom renderers
• Included comprehensive test coverage and demo page

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
src/button-dropdown/interfaces.ts	Added TypeScript interfaces for RenderItem types and ItemRenderer function signature
src/button-dropdown/index.tsx	Added renderItem prop to component entry point
src/button-dropdown/internal.tsx	Threaded renderItem prop through internal implementation
src/button-dropdown/items-list.tsx	Added index and renderItem/parentProps prop threading to list rendering
src/button-dropdown/item-element/index.tsx	Implemented custom rendering logic for individual items with proper prop construction
src/button-dropdown/item-element/styles.scss	Added no-content-styling class to remove default item padding/styling
src/button-dropdown/category-elements/*.tsx	Implemented custom rendering for all category element variants (standard, expandable, mobile)
src/button-dropdown/category-elements/styles.scss	Added no-content-styling class for category headers
src/button-dropdown/tests/render-item.test.tsx	Comprehensive test suite covering all item types and custom rendering scenarios
src/button-dropdown/tests/mobile-expandable-category.test.tsx	Added test for mobile expandable category custom rendering
pages/button-dropdown/custom-render-item.page.tsx	Demo page showing usage examples
src/tests/snapshot-tests/snapshots/documenter.test.ts.snap	Updated snapshot with new prop documentation

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[Copilot]

Pull request overview

Copilot reviewed 14 out of 14 changed files in this pull request and generated 5 comments.

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