Update promote_servicedesk user callout to BannerComponent

What does this MR do and why?

This MR updates the user callout in app/views/shared/promotions/_promote_servicedesk.html.haml to the ViewComponent to make it Pajamas complaint. The MR also adds an action button that leads to the documentation to the banner.

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Use not licensed GDK
2. Go to Project -> Settings -> General -> Service Desk

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.

Review progress:

• UX review
• test Quality review
• frontend developer review
• frontend maintainer review
• backend developer review
• backend maintainer review

Closes to #362760 (closed)