cluster/manifests: disable loading routing table

Set the `source-poll-timeout` flag to the max int64 value to disable loading the routing table for the data client. The routing table loads by default whenever a data-client config is present. In this case, the config is only needed, so the filters get added to the registry for validation

Author: vlktna

cluster/manifests/02-skipper-validation-webhook/deployment.yaml

@@ -102,6 +102,7 @@ spec:
           - "-kubernetes-path-mode=path-prefix"
           - "-enable-kubernetes-endpointslices={{ .Cluster.ConfigItems.skipper_endpointslices_enabled }}"
           - "-enable-advanced-validation={{ .Cluster.ConfigItems.enable_advanced_validation }}"
+          - "-source-poll-timeout=9223372036854775807" # Disable loading routing table in dataclient
           - "-metrics-flavour=prometheus"
           - "-metrics-exp-decay-sample"
           - "-enable-prometheus-start-label={{ .Cluster.ConfigItems.skipper_prometheus_start_label_enabled }}"