Feature: #106637 - Implement accessible combobox pattern 

See forge#106637

Description 

A new ARIA 1.2–compliant combobox web component has been introduced, replacing the legacy value picker select pattern. The implementation follows the W3C accessibility guidelines and provides complete keyboard navigation support.

FormEngine elements, including EmailElement , InputTextElement , and NumberElement , have been updated to use the new combobox component instead of the previous value picker implementation. The link browser components have also been adapted to use the combobox pattern.

Impact 

The new combobox component offers full keyboard navigation using the arrow keys, Enter, Tab, and Escape.

It includes visual selection indicators with checkmarks and a clear button for resetting the input value, improving accessibility and overall usability in the TYPO3 backend.