Reverting setting HPA namespace variable (#698)

Co-authored-by: Jorge Turrado Ferrero <Jorge_turrado@hotmail.es>

Author: Rotzke

keda/templates/metrics-server/clusterrolebinding.yaml

@@ -59,5 +59,5 @@ roleRef:
 subjects:
 - kind: ServiceAccount
   name: horizontal-pod-autoscaler
-  namespace: {{ .Values.rbac.controlPlaneServiceAccountsNamespace }}
+  namespace: kube-system
 {{- end -}}