port-mbim: increase timeout of first command after port open

The port open operation may be happening very early after the device
has booted, so let's give the module some more time to reply the very
first MBIM query we do. The original 10s seems to be a bit tight in
some cases.

See https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/issues/405#note_1006746

src/mm-port-mbim.c

@@ -533,7 +533,7 @@ mbim_query_device_services (GTask *task)
     message = mbim_message_device_services_query_new (NULL);
     mbim_device_command (self->priv->mbim_device,
                          message,
-                         10,
+                         20,
                          NULL,
                          (GAsyncReadyCallback)mbim_query_device_services_ready,
                          task);