test(bridge): fix bridge map type filed converters

now the converters on map type fields only work at the wrapping map
level but not the values

apps/emqx_bridge/src/schema/emqx_bridge_schema.erl

@@ -230,7 +230,12 @@ webhook_bridge_converter(Conf0, _HoconOpts) ->
         undefined ->
             undefined;
         _ ->
-            do_convert_webhook_config(Conf1)
+            maps:map(
+                fun(_Name, Conf) ->
+                    do_convert_webhook_config(Conf)
+                end,
+                Conf1
+            )
     end.
 
 do_convert_webhook_config(

lib-ee/emqx_ee_bridge/src/emqx_ee_bridge.erl

@@ -181,7 +181,7 @@ kafka_structs() ->
                 #{
                     desc => <<"Kafka Producer Bridge Config">>,
                     required => false,
-                    converter => fun emqx_bridge_kafka:kafka_producer_converter/2
+                    converter => fun kafka_producer_converter/2
                 }
             )},
         {kafka_consumer,
@@ -264,3 +264,13 @@ sqlserver_structs() ->
                 }
             )}
     ].
+
+kafka_producer_converter(undefined, _) ->
+    undefined;
+kafka_producer_converter(Map, Opts) ->
+    maps:map(
+        fun(_Name, Config) ->
+            emqx_bridge_kafka:kafka_producer_converter(Config, Opts)
+        end,
+        Map
+    ).