authentik: ClientIP session affinity on server service

Tofu/terraform applies against authentik race across the 3 server
replicas: a create on one pod followed by an immediate read-back on
another returns stale data ("inconsistent result after apply",
goauthentik/terraform-provider-authentik#954). ClientIP affinity pins
an apply run to a single pod until the upstream bug is fixed.

- Set server.service.sessionAffinity: ClientIP with
  clientIP.timeoutSeconds: 60 in the au-syd1 authentik overlay

apps/overlays/au-syd1/authentik/values.yaml

@@ -78,6 +78,11 @@ server:
     configmap.reloader.stakater.com/auto: "true"
   ingress:
     enabled: false
+  service:
+    sessionAffinity: ClientIP
+    sessionAffinityConfig:
+      clientIP:
+        timeoutSeconds: 60
   resources:
     limits:
       cpu: "2"