Python API: fix reader_listener option (#5487)

Fixes #5484

(cherry picked from commit 6df7cec6)

pulsar-client-cpp/python/src/config.cc

@@ -156,7 +156,7 @@ void export_config() {
             ;
 
     class_<ReaderConfiguration>("ReaderConfiguration")
-            .def("message_listener", &ReaderConfiguration_setReaderListener, return_self<>())
+            .def("reader_listener", &ReaderConfiguration_setReaderListener, return_self<>())
             .def("schema", &ReaderConfiguration::getSchema, return_value_policy<copy_const_reference>())
             .def("schema", &ReaderConfiguration::setSchema, return_self<>())
             .def("receiver_queue_size", &ReaderConfiguration::getReceiverQueueSize)