Clarify config of private links for hosted runners
What does this MR do and why?
This merge request updates the documentation for hosted runners for GitLab Dedicated. It clarifies that private link config is automated between a GitLab instance or a Prometheus instance and hosted runners when an outbound private link is configured for GitLab Dedicated.
This MR also makes some improvements to the Outbound private link section and related content in that page.
Resolves https://gitlab.com/gitlab-com/gl-infra/gitlab-dedicated/team/-/issues/6027
Edited by Lysanne Pinto