[Mixin] MimirGossipMembersMismatch always fires in GEM deployments

[eamonryan]

Describe the bug

The alert MimirGossipMembersMismatch always fires in GEM deployments because the admin-api is not included in the list of job names, so there is always a mismatch of exactly the number of admin-api pods.

To Reproduce

Steps to reproduce the behavior:

1. Deploy GEM via the mimir-distributed helm chart
2. Set up metamonitoring via the Grafana Cloud self-hosted Mimir integration
3. See the MimirGossipMembersMismatch alert starts firing at the soonest opportunity

Expected behavior

The alert should not fire under normal circumstances since the count of memberlist_client_cluster_members_count should match the number of pods that are up.

Environment

• Infrastructure: Kubernetes
• Deployment tool: Helm
• GEM: 2.9.x

Additional Context