feat: Support secondaryText and labelTag for button-dropdown

[kuahuu]

Description

Added support for secondaryText and labelTag properties to ButtonDropdown items, enabling richer item content similar to other Cloudscape components like Select and Multiselect.

This PR also added deprecated annotation for description prop for button dropdown item.

New features:
secondaryText: Displays additional descriptive text below the main item text
labelTag: Adds a visual tag/label to items for categorization or status indication

Implementation details:

• Extended ButtonDropdownProps.Item interface to include the new properties
• Updated ItemElement component to render secondary text and label tags
• Added corresponding styles for proper layout and visual hierarchy
• Added comprehensive test coverage for the new functionality
• Add deprecated annotation into the description prop
• Introduce findSecondaryText and findLabelTag test utils

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

How has this been tested?

Unit Tests:

• Added tests in button-dropdown-items.test.tsx for secondaryText rendering
• Added tests in button-dropdown-keyboard.test.tsx for keyboard navigation with secondaryText
• All existing ButtonDropdown tests continue to pass

Manual Testing:

• Verified visual appearance and layout of items with secondaryText and labelTag
• Tested keyboard navigation and accessibility
• Confirmed backward compatibility with existing ButtonDropdown usage

Reviewers can test by running:

npm test -- --testPathPattern="button-dropdown"
npm run test:integ -- --testPathPattern="button-dropdown"

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 96.99%. Comparing base (abb494e) to head (1764486).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3844   +/-   ##
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  Coverage   96.99%   96.99%           
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  Files         861      861           
  Lines       25207    25213    +6     
  Branches     9098     9103    +5     
=======================================
+ Hits        24450    24456    +6     
  Misses        710      710           
  Partials       47       47           

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[kuahuu]

Rebased from the latest origin main and resolve the conflict.

changes applied