fix(truncate): fix missing `await` in truncate all models with cascade (#12664)

lib/sequelize.js

@@ -819,7 +819,7 @@ class Sequelize {
     }, { reverse: false });
 
     if (options && options.cascade) {
-      for (const model of models) model.truncate(options);
+      for (const model of models) await model.truncate(options);
     } else {
       await Promise.all(models.map(model => model.truncate(options)));
     }