Migrates the alert status dropdown to be pajamas compliant

What does this MR do and why?

Migrates the alert status dropdown to be pajamas compliant

Uses the new GlCollapsibleListbox component whilst preserving all the current functionality.

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

Note: They look different before and after. This is deliberate, we're making things that weren't pajamas compliant, compliant. The UI will change.

Before	After

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Go to Monitor > Alerts
2. If you see the empty state, follow the steps to set up a new integration
3. Test the dropdown in the list view. You should be able to update the status inline
4. Click on one of the alerts to see the detail page
5. Edit the status in the sidebar. You should be able to interact with it just like you would when assigning a user to an issue.

Set up a new alerts integration

alerts.mov

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #413491