Update cloud-metrics-grafana to 7.3.9 (#478)

Co-authored-by: mkjpryor <642657+mkjpryor@users.noreply.github.com>

roles/cloud_metrics/defaults/main.yml

@@ -3,7 +3,7 @@
 # The chart to use for Grafana
 cloud_metrics_grafana_chart_repo: https://grafana.github.io/helm-charts
 cloud_metrics_grafana_chart_name: grafana
-cloud_metrics_grafana_chart_version: 7.3.8
+cloud_metrics_grafana_chart_version: 7.3.9
 
 # Release information for the Grafana release
 # By default, deploy into the same namespace as Azimuth