Extend ErrorAlert Vue component with buttons

What does this MR do and why?

Extend ErrorAlert Vue component with buttons

This component uses the GlAlert component, which offers the possibility for primary and secondary buttons. We want to make the usage of the buttons possible. Helps resolving https://gitlab.com/gitlab-org/gitlab/-/issues/455364 and blocks !155737 (merged)

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

Before	After

How to set up and validate locally

Related to #467263