Allow ci-runners to contribute to our overall availability score

While compiling our availability report for June https://gitlab.com/gitlab-com/gl-infra/reliability-reports/-/issues/178 and as a followup to production#14628 (closed) I believe we should probably start allowing CI runners to have weight in our overall availability.

Current this is set to zero in https://gitlab.com/gitlab-com/runbooks/-/blob/10ad96cf73c0e37f6b5e793092478abf38df707c/services/service-catalog.yml#L1777 .

@rehab wdyt, would it be possible to look back to see if this would have had any impact on availability scores prior? @reprazent can you think of any reason why it shouldn't be included?