network: trigger 'network_updated' as soon as set_parameters finishes

e.g. kivy GUI refreshes some fields based on this callback;
this should result in faster refreshes
(otherwise e.g. when switching servers, a callback might only come if
we successfully connect to the new server; or if an unrelated event
triggers it)

electrum/network.py

@@ -636,6 +636,7 @@ class Network(Logger, NetworkRetryManager[ServerAddr]):
                 await self.switch_to_interface(server)
             else:
                 await self.switch_lagging_interface()
+        util.trigger_callback('network_updated')
 
     def _maybe_set_oneserver(self) -> None:
         oneserver = bool(self.config.get('oneserver', False))