[Server] modify ac_id field of CONFIG message for replay sessions (#2616)

* [server] Send real ID with CONFIG message instead of the original ID.

* Fix pprz_connect to accept non integer ac ids.
Makes "conf_by_id" docstring true.

* Makes suggested modifications.

sw/lib/python/pprz_connect.py

@@ -216,7 +216,7 @@ class PprzConnect(object):
                     msg['flight_plan'], msg['settings'], msg['radio'],
                     msg['default_gui_color'])
             self._conf_list_by_name[conf.name] = conf
-            self._conf_list_by_id[int(conf.id)] = conf
+            self._conf_list_by_id[conf.id] = conf
             if self._notify is not None:
                 self._notify(conf) # user defined general callback
             if self.verbose: