fix uid/gid vars for Synapse Admin

roles/custom/matrix-synapse-admin/templates/systemd/matrix-synapse-admin.service.j2

@@ -22,7 +22,7 @@ ExecStartPre={{ devture_systemd_docker_base_host_command_docker }} create \
 			--log-driver=none \
 			--cap-drop=ALL \
 			--read-only \
-			--user={{ matrix_synapse_admin_container_user_uid }}:{{ matrix_synapse_admin_container_user_gid }} \
+			--user={{ matrix_synapse_admin_container_uid }}:{{ matrix_synapse_admin_container_gid }} \
 			--network={{ matrix_synapse_admin_container_network }} \
 			{% if matrix_synapse_admin_container_http_host_bind_port %}
 			-p {{ matrix_synapse_admin_container_http_host_bind_port }}:8080 \