feat(prom): expose cluster id in identity

(cherry picked from commit 84de860)

Author: johanneswuerbach

deps/rabbitmq_prometheus/src/collectors/prometheus_rabbitmq_core_metrics_collector.erl

@@ -321,6 +321,7 @@ identity_info() ->
             [
                 {rabbitmq_node, node()},
                 {rabbitmq_cluster, rabbit_nodes:cluster_name()}
+                {rabbitmq_cluster_permanent_id, rabbit_nodes:persistent_cluster_id()}
             ],
             1
         }]

deps/rabbitmq_prometheus/test/rabbit_prometheus_http_SUITE.erl

@@ -376,6 +376,7 @@ identity_info_test(Config) ->
     ?assertEqual(match, re:run(Body, "^rabbitmq_identity_info{", [{capture, none}, multiline])),
     ?assertEqual(match, re:run(Body, "rabbitmq_node=", [{capture, none}])),
     ?assertEqual(match, re:run(Body, "rabbitmq_cluster=", [{capture, none}])).
+    ?assertEqual(match, re:run(Body, "rabbitmq_cluster_permanent_id=", [{capture, none}])).
 
 specific_erlang_metrics_present_test(Config) ->
     {_Headers, Body} = http_get_with_pal(Config, [], 200),