refactor: no support for listener level authentication for now

apps/emqx/src/emqx_schema.erl

@@ -1880,7 +1880,9 @@ mqtt_listener(Bind) ->
                         default => <<"3s">>
                     }
                 )},
-            {?EMQX_AUTHENTICATION_CONFIG_ROOT_NAME, authentication(listener)}
+            {?EMQX_AUTHENTICATION_CONFIG_ROOT_NAME, (authentication(listener))#{
+                importance => ?IMPORTANCE_HIDDEN
+            }}
         ].
 
 base_listener(Bind) ->

apps/emqx_gateway/src/emqx_gateway_schema.erl

@@ -580,6 +580,8 @@ authentication_schema() ->
         #{
             required => {false, recursively},
             desc => ?DESC(gateway_common_authentication),
+            %% we do not expose this to the user for now
+            importance => ?IMPORTANCE_HIDDEN,
             examples => emqx_authn_api:authenticator_examples()
         }
     ).