Add and use gl_badge_tag helper in runner settings

What does this MR do and why?

This adds a new Rails helper, gl_badge_tag, that creates the markup for a Pajamas-compliant badge component. The markup should be equivalent to that produced by the Vue implementation GlBadge in GitLab UI.

This also uses the helper in app/views/shared/runners/_runner_description.html.haml, addressing #344413 (closed).

Screenshots or screen recordings

Variations

How to set up and validate locally

To view variations demo

Apply this patch, then visit <your gdk host>/<some-group>/<some-project>/-/security/configuration.

Runner description change

Visit <your gdk host>/<some-group>/<some-project>/-/settings/ci_cd#js-runners-settings.

There should be no visual change.

Before	After

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.