Opening CI/CD settings page when project has many runners is very slow

For projects that have A LOT of registered runners (at about 1,000 this problem is known to show up - see https://gitlab.com/gitlab-com/gl-infra/infrastructure/issues/7642). The CI/CD Settings page is very slow to load.

This happens when a lot of runners have been registered, they don't all need to be active any longer, which seems to happen when users are frequently registering new runners and not removing them.