selectSetter不支持清除

## **Describe the bug (required)** / **详细描述 bug（必填）**
selectSetter 不支持清除

A clear and concise description of what the bug is. / 请提供清晰且精确的 bug 描述
selectSetter 选择后不支持清除
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## **Expected behavior (required)** / **预期行为（必填，非常重要）**
A clear and concise description of what did you expect to happen. / 请清晰和精确的描述你预期的行为
选择后支持删除已选择的，恢复默认值

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## **Screenshots (optional)** / **bug 截图（可选）**
Sceenshots for further information. (If applicable.) / 一些有用的截图将会帮助我们更好的明确以及定位问题

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## **Environments (please complete the following information) (required):** / **请提供如下信息（必填）**
- AliLowCodeEngine version: [e.g. 1.0.0] / 低代码引擎版本
- AliLowCodeEngineExt version: [1.0.0-beta.2] / 低代码引擎扩展包版本

Start by locating the selectSetter implementation and any related tests; the issue does not identify file paths, tests, or package versions. Done means a selected value can be cleared and the default value is restored, with the behavior covered by an appropriate test.

Written by the indexing model from the issue text.