Fix missing highlight of items on keyboard navigation in dropdown when using popover

[mark-drastrup]

Which issue does this PR close?

This PR closes #3062

What is the new behavior?

Items will now be highlighted when using the arrow keys to navigate a dropdown with [usePopover]="true".

Does this PR introduce a breaking change?

• Yes
• No

Are there any additional context?

Checklist:

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When the pull request has been approved it will be merged to develop by Team Kirby.

[jakobe]

Awesome!