[DevOps Adoption] Modify CI runner queries decomposition

The following query still causes cross-joins between the main and CI database: https://gitlab.com/gitlab-org/gitlab/-/blob/master/ee/lib/analytics/devops_adoption/snapshot_calculator.rb#L65

The related scope will be unblocked by the implementation of this issue: #336432 (closed)

Related links

• Manage: Optimize - Decomposition impact
• Original issue

Related to #337541 (closed).