ike: Add an additional but separate AEAD proposal to CHILD config

This currently has no effect: We don't include AEAD algorithms in the default
ESP proposal, as we don't know if it is supported by the backend. But as we
hopefully get an algorithm query mechanism on kernel interfaces some day, we
add the appropriate functionality nonetheless.

src/conftest/config.c

@@ -181,6 +181,8 @@ static child_cfg_t *load_child_config(private_config_t *this,
 	else
 	{
 		child_cfg->add_proposal(child_cfg, proposal_create_default(PROTO_ESP));
+		child_cfg->add_proposal(child_cfg,
+								proposal_create_default_aead(PROTO_ESP));
 	}
 
 	token = settings->get_str(settings, "configs.%s.%s.lts", NULL, config, child);