xim: clear callback preedit on owner loss

tests/unit_test.c

@@ -145,6 +145,7 @@ static const struct ct_test tests[] = {
 	{ "xim/callback-unicode", xim_adapter_callback_unicode },
 	{ "xim/callback-cleanup", xim_adapter_callback_cleanup },
 	{ "xim/callback-transfer", xim_adapter_callback_transfer },
+	{ "xim/callback-owner-loss", xim_adapter_callback_owner_loss },
 	{ "xim/commit-encoding", xim_adapter_commit_encoding },
 };