Enable mTLS for Promtail metrics

Relates #10 (closed)

Adds mTLS to the service monitor and removes the exception.

chart/templates/bigbang/peerauthentication/promtail.yaml

@@ -10,10 +10,4 @@ spec:
   selector:
     matchLabels:
       {{- include "promtail.selectorLabels" . | nindent 6 }}
-  {{- if and (eq .Values.istio.mtls.mode "STRICT") (.Capabilities.APIVersions.Has "monitoring.coreos.com/v1") .Values.serviceMonitor.enabled }}
-  # Monitoring exception
-  portLevelMtls:
-    "{{ .Values.config.serverPort }}":
-      mode: PERMISSIVE
-  {{- end }}
 {{- end }}