chore(deps): update prometheus-stack to v56.8.0

| datasource | package               | from   | to     |
| ---------- | --------------------- | ------ | ------ |
| helm       | kube-prometheus-stack | 56.6.2 | 56.8.0 |

src/prometheus-stack/common/zarf.yaml

@@ -15,6 +15,6 @@ components:
       - name: kube-prometheus-stack
         namespace: monitoring
         url: https://prometheus-community.github.io/helm-charts
-        version: 56.6.2
+        version: 56.8.0
         valuesFiles:
           - "../values/values.yaml"