Add dropdown keyboard accessibility

[eelikivi]

Linked issue: #5609

Problem
The year and month dropdowns are not accessible via keyboard. The dropdown toggles cannot be focused, and the dropdown options cannot be navigated using arrow keys or selected with the Enter key.

Changes

• Changed the dropdown read view components from div to button to allow keyboard focusing.
• Added keyboard support for dropdown option components. Arrow keys can now be used to navigate the list, and the Enter key can be used to select an option.

Contribution checklist

• I have followed the contributing guidelines.
• I have added sufficient test coverage for my changes.
• I have formatted my code with Prettier and checked for linting issues with ESLint for code readability.

[martijnrusschen]

Thanks, this looks interesting. Need to trigger the workflows to run the test suite.

[martijnrusschen]

Can you try rebasing with the latest changes on the main branch?

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.23%. Comparing base (6d64eff) to head (0f2ba5b).
⚠️ Report is 13 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5728      +/-   ##
==========================================
+ Coverage   97.19%   97.23%   +0.03%     
==========================================
  Files          30       30              
  Lines        3391     3436      +45     
  Branches     1421     1440      +19     
==========================================
+ Hits         3296     3341      +45     
  Misses         95       95              

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