Fix gitpod_workspace_regular_not_active_percentage_mk2, and temporarily disable related alerts (#18332)

We'll likely replace the alerts too, using one that detects anomalies given zscore.

Related to ENG-20

Author: kylos101

operations/observability/mixins/workspace/rules/satellite/workspaces.yaml

@@ -15,13 +15,13 @@ spec:
     rules:
     - record: gitpod_workspace_regular_not_active_percentage_mk2
       expr: |
-        gitpod_ws_manager_mk2_workspace_activity_total{active="false"} / gitpod_ws_manager_mk2_workspace_activity_total
+        sum(gitpod_ws_manager_mk2_workspace_activity_total{active="false"}) by (cluster) / sum(gitpod_ws_manager_mk2_workspace_activity_total) by (cluster)
 
   - name: workspace-alerts
     rules:
     - alert: GitpodWorkspaceTooManyRegularNotActiveMk2
       labels:
-        severity: critical
+        severity: warning
       for: 10m
       annotations:
         runbook_url: https://github.com/gitpod-io/runbooks/blob/main/runbooks/GitpodWorkspaceTooManyRegularNotActive.md
@@ -34,7 +34,7 @@ spec:
 
     - alert: GitpodWorkspacesNotStartingMk2
       labels:
-        severity: critical
+        severity: warning
       for: 10m
       annotations:
         runbook_url: https://github.com/gitpod-io/runbooks/blob/main/runbooks/GitpodWorkspaceNotStarting.md