Fix matrix_registration_shared_secret for Dendrite

group_vars/matrix_servers

@@ -2078,7 +2078,13 @@ matrix_registration_container_http_host_bind_port: "{{ '' if matrix_nginx_proxy_
 
 matrix_registration_riot_instance: "{{ ('https://' + matrix_server_fqn_element) if matrix_client_element_enabled else 'https://riot.im/app/' }}"
 
-matrix_registration_shared_secret: "{{ matrix_synapse_registration_shared_secret if matrix_synapse_enabled else '' }}"
+matrix_registration_shared_secret: |-
+  {{
+    {
+      'synapse': matrix_synapse_registration_shared_secret,
+      'dendrite': matrix_dendrite_registration_shared_secret,
+    }[matrix_homeserver_implementation]
+  }}
 
 matrix_registration_server_location: "{{ matrix_homeserver_container_url }}"