Correct receipts worker being marked as isSingle

[benbz]

Fixes up #640 and so has a copy of the changelog

[github-actions]

dyff of changes in rendered templates of CI manifests

Full contents of manifests and dyffs are available in https://github.com/element-hq/ess-helm/actions/runs/16718641369/artifacts/3679837488

synapse-worker-example-values.yaml

@@ ConfigMap/ess-ci/release-name-haproxy - data.haproxy.cfg @@
  global
    maxconn 40000
    log stdout format raw local0 info
  
  
  [323 lines unchanged)]
  
    option httpchk
    http-check connect port 8080
    http-check send meth GET uri /health
    # Use DNS SRV service discovery on the headless service
-   server-template receipts 1 _synapse-http._tcp.release-name-synapse-receipts.ess-ci.svc.cluster.local resolvers kubedns init-addr none check
+   server-template receipts 20 _synapse-http._tcp.release-name-synapse-receipts.ess-ci.svc.cluster.local resolvers kubedns init-addr none check
  
  backend synapse-sliding-sync
    option httpchk
    http-check connect port 8080
  
  [81 lines unchanged)]
  
  # a fake backend which fonxes every request with a 500. Useful for
  # handling overloads etc.
  backend return_500
    http-request deny deny_status 500



@@ Deployment/ess-ci/release-name-haproxy - metadata.labels.k8s.element.io/shared-haproxy-config-hash @@
- 031ab7071c95aa796a6458de1c7cef06795dc163
+ a683cbf7b2694f471fcc6d6a2a4aa9406f97e548

@@ Deployment/ess-ci/release-name-haproxy - spec.template.metadata.labels.k8s.element.io/shared-haproxy-config-hash @@
- 031ab7071c95aa796a6458de1c7cef06795dc163
+ a683cbf7b2694f471fcc6d6a2a4aa9406f97e548