fix(cv-combo-box): accessibility violations

[peterzaccha]

Contributes to #

## What did you do?

Fix accessibility violation: nested-interactive caused by using a listbox role on a div with two buttons

this fix inspired by the same component in the react carbon lib https://react.carbondesignsystem.com/?path=/story/components-combobox--default

## Why did you do it?

How have you tested it?

Were docs updated if needed?

• [ ] N/A
• [ ] No
• [ ] Yes