feat: add `broker` root to hot-config schema

apps/emqx_management/src/emqx_mgmt_api_configs.erl

@@ -53,7 +53,8 @@
     <<"alarm">>,
     <<"sys_topics">>,
     <<"sysmon">>,
-    <<"log">>
+    <<"log">>,
+    <<"broker">>
     | ?ROOT_KEYS_EE
 ]).