Add extra alerts plus fix existing alerts for Dedicated Hosted Runners (DHR)
https://gitlab.com/gitlab-com/gl-infra/gitlab-dedicated/team/-/issues/10355
added HostedRunnersServiceCapacityUtilizationHighSingleShard as a non-paging alert.
fixed HostedRunnersServicePendingBuildsApdexSLOViolationSingleShard and HostedRunnersServiceQueuingQueriesDurationApdexSLOViolation by changing queuing queries duration to monitor gitlab_runner_job_queue_duration_seconds_* (which works and returns data) instead of gitlab_ci_queue_retrieval_duration_seconds_* (which is empty)
also added a screenshot of an error message for CustomersDB which I was meant to include a while ago in a very previous MR.
Edited by Zoe Braddock