Alignment problem with error banner.

Following a discussion in slack, there's a bit of confusion on which banner width to use.

Per documentation we should expand this to the full width of the page.

A global alert impacts the entire experience, is full-width, and is placed directly below the navigation bar. For example, after a user has authenticated an alert appears that states, “Your subscription has expired.”

See originating issue for context. https://gitlab.com/gitlab-org/gitlab/-/issues/237905

Proposal

In issue - Normal	Wide	Project / Group viewer

Implementation plan

For this issue we will only take care of the Open registration is enabled on your instance and Auto DevOps pipeline has been enabled alerts. The rest will be taken care of in a follow-up issue.

1. Create a new HAML partial (_global_alert.html.haml). '
   • Will handle all of the styling
   • Will have a yield statement for the alert content
   • Will have a title local for the title
   • Will have a variant local for the alert type
2. Refactor app/views/layouts/header/_registration_enabled_callout.html.haml to use this partial
3. Refactor app/views/shared/_auto_devops_implicitly_enabled_banner.html.haml to use this partial
4. Open up follow-up issues to refactor the rest of the global alerts