Alan Guo Xiang Tan e5566b8519
FIX: Error encountered when adding child object in object setting editor (#26259)
Why this change?

If an object doesn't have any child objects for a particular property
and we try to add one through the editor, an error will be raised.

```
Cannot read properties of undefined (reading 'push')
    at SchemaThemeSettingEditor.addItem (editor.js:190:1)
```
2024-03-21 11:35:49 +08:00
..