fix: remove redundant restart message from update launchd path

launchd_restart() already prints stop/start confirmation via its
internal helpers — the extra 'Gateway restarted via launchd' line
was redundant. Update test assertion to match.

tests/hermes_cli/test_update_gateway_restart.py

@@ -312,7 +312,7 @@ class TestCmdUpdateLaunchdRestart:
             cmd_update(mock_args)
 
         captured = capsys.readouterr().out
-        assert "Gateway restarted via launchd" in captured
+        assert "Restarting gateway service" in captured
         assert "Restart it with: hermes gateway run" not in captured
         mock_launchd_restart.assert_called_once_with()