数据源导入导出出错

## **Describe the bug (required)** / **详细描述 bug（必填）**
A clear and concise description of what the bug is. / 请提供清晰且精确的 bug 描述
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点击导出再导入显示格式有误

## **To Reproduce (required)** / **如何复现 bug？（必填，非常重要）**
https://lowcode-engine.cn/demo/demo-general/index.html
点击导出再导入显示格式有误

Open the linked lowcode-engine demo and reproduce the issue by exporting a data source and importing it again. Inspect the resulting format error and trace the export/import entry points from the demo; no source file or test is named in the report. Done means a round trip completes without a format error.

Written by the indexing model from the issue text.