Remove guard condition listener

Signed-off-by: Mauro Passerino <mpasserino@irobot.com>

rmw/include/rmw/rmw.h

@@ -2861,29 +2861,6 @@ rmw_client_set_listener_callback(
   rmw_listener_callback_t listener_callback,
   const void * user_data);
 
-/// Set callback function of the rmw guard condition listener.
-/**
- * This API sets the callback function which will be called whenever the
- * guard condition listener is notified about the guard condition being triggered.
- * The callback may be called from a thread that the rmw implementation
- * created, rather than a thread owned by the user, i.e. some thread other
- * than user owned threads calling rmw functions such as rmw_wait() or
- * rmw_publish().
- *
- * \param[in] rmw_guard_condition The rmw guard condition to which the listener belongs
- * \param[in] listener_callback The callback to be called by the listener
- * \param[in] user_data Used as arg for the call of the listener_callback
- * \return `RMW_RET_OK` if callback was set to the listener, or
- * \return `RMW_RET_UNSUPPORTED` if the API is not implemented in the dds implementation
- */
-RMW_PUBLIC
-RMW_WARN_UNUSED
-rmw_ret_t
-rmw_guard_condition_set_listener_callback(
-  rmw_guard_condition_t * rmw_guard_condition,
-  rmw_listener_callback_t listener_callback,
-  const void * user_data);
-
 /// Set callback function of the rmw event listener.
 /**
  * This API sets the callback function which will be called whenever the