util.EventListener: don't log "registering callback"

IMO this is just too spammy to log in the general case when running with -v

electrum/util.py

@@ -1735,12 +1735,12 @@ class EventListener:
 
     def register_callbacks(self):
         for name, method in self._list_callbacks():
-            _logger.info(f'registering callback {method}')
+            #_logger.debug(f'registering callback {method}')
             register_callback(method, [name])
 
     def unregister_callbacks(self):
         for name, method in self._list_callbacks():
-            _logger.info(f'unregistering callback {method}')
+            #_logger.debug(f'unregistering callback {method}')
             unregister_callback(method)