fix(sys): fix bad swagger example format

apps/emqx_management/src/emqx_mgmt_api_configs.erl

@@ -57,7 +57,8 @@
     <<"delayed">>,
     <<"event_message">>,
     <<"prometheus">>,
-    <<"telemetry">>
+    <<"telemetry">>,
+    <<"sys_topics">>
     ] ++ global_zone_roots()
 ).
 

apps/emqx_management/src/emqx_mgmt_api_sys.erl

@@ -76,7 +76,7 @@ schema("/mqtt/sys_topics") ->
      }.
 
 schema_sys_topics() ->
-    emqx_dashboard_swagger:schema_with_examples(
+    emqx_dashboard_swagger:schema_with_example(
       hoconsc:ref(emqx_schema, "sys_topics"), example_sys_topics()).
 
 example_sys_topics() ->