introspect: handle strdup failures

Abort and clean up the dict copy when allocation fails.

src/pipewire/introspect.c

@@ -94,12 +94,18 @@ static struct spa_dict *pw_spa_dict_copy(struct spa_dict *dict)
 	for (i = 0; i < dict->n_items; i++) {
 		items[i].key = strdup(dict->items[i].key);
 		items[i].value = dict->items[i].value ? strdup(dict->items[i].value) : NULL;
+		if (items[i].key == NULL ||
+		    (dict->items[i].value != NULL && items[i].value == NULL))
+			goto no_key;
 	}
 	return copy;
 
-      no_items:
+no_key:
+	pw_spa_dict_destroy(copy);
+	return NULL;
+no_items:
 	free(copy);
-      no_mem:
+no_mem:
 	return NULL;
 }