Added Option for Grafana Alertmanager (#2498)

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Co-authored-by: shamoon <4887959+shamoon@users.noreply.github.com>

src/widgets/grafana/widget.js

@@ -8,6 +8,9 @@ const widget = {
     alerts: {
       endpoint: "alerts",
     },
+    alertmanager: {
+      endpoint: "alertmanager/grafana/api/v2/alerts",
+    },
     stats: {
       endpoint: "admin/stats",
       validate: ["dashboards"],