设置ArraySetter之后，拿到的数据不应该是数组格式嘛？


meta.ts
```
import type { IPublicTypeComponentMetadata, IPublicTypeSnippet } from "@alilc/lowcode-types";

const DemoTableMeta: IPublicTypeComponentMetadata = {
"componentName": "DemoTable",
"title": "DemoTable",
"docUrl": "",
"screenshot": "",
"devMode": "proCode",
"configure": {
"props": [
{
"title": { "label": '表格列', "tip": '表格列的配置描述，具体项见下表' },
"name": 'columns',
"setter": {
"componentName": 'ArraySetter',
"props": {
"itemSetter": {
"componentName": 'ObjectSetter',
"props": {
"config": {
"items": [
{
"name": 'title',
"title": { "label": '列标题', "tip": 'title | 列标题' },
"setter": "StringSetter"
},
{
"name": 'dataIndex',
"title": { "label": '数据字段', "tip": 'dataIndex | 数据字段' },
"setter": 'StringSetter',
"isRequired": true,
},
],
},
},
"defaultValue": { "title": '标题' },
},
},
"defaultValue": []
},
},
],
"supports": {
"style": true
},
"component": {}
},
};
const snippets: IPublicTypeSnippet[] = [
{
"title": "DemoTable",
"screenshot": "",
"schema": {
"componentName": "DemoTable",
"props": {}
}
}
];

export default {
...DemoTableMeta,
snippets
};

```

Start with the meta.ts reproduction and inspect how ArraySetter and its ObjectSetter item configuration serialize the columns value. Reproduce the reported result, then trace whether the returned value is expected to be an array and identify the relevant existing test location. Done means the configured columns data has a confirmed, documented output shape and a regression test if the behavior is incorrect.

Written by the indexing model from the issue text.