Fix: Prevent default behavior while scrolling using arrow keys in a h…

[Jellepostma]

…orizontal listbox

What I did

1. Added ev.preventDefault in the left and right arrow key handlers in the listboxmixin, to prevent the listbox from scrolling unintended when using these keys to navigate through the list when it is horizontal. The same fix has been already applied for vertical scrolling.

How to test

1. On the current master, check the horizontal listbox example using a browser window that is smaller than the width of the listbox. Using arrow keys, it will start scrolling even if the next option is completely in view due to default scrolling behavior of these arrow keys.

[changeset-bot]

🦋 Changeset detected

Latest commit: 1ea9f29

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@lion/listbox	Patch

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[CLAassistant]

All committers have signed the CLA.

[gerjanvangeest]

Hi Jelle, thanks for the contribution 💪

Can you add a changeset (yarn changeset) to make the change also ready for release?

[jorenbroekema]

@Jellepostma looks like you still need to sign the CLA agreement

Edit: as for the CI, needed to rebase on latest master, CI should be happy now

[Jellepostma]

@jorenbroekema Done! Thank you for the rebase :)