Fix variable name typo

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/1397

roles/matrix-synapse/templates/synapse/homeserver.yaml.j2

@@ -302,7 +302,7 @@ listeners:
 {% if matrix_synapse_federation_port_enabled %}
   # Unsecure HTTP listener (Federation API): for when matrix traffic passes through a reverse proxy
   # that unwraps TLS.
-  - port: {{ matrix_synapse_container_default_federation_port|to_json }}
+  - port: {{ matrix_synapse_container_federation_port|to_json }}
     tls: false
     bind_addresses: ['::']
     type: http