[Bug]: Pydantic serialization error

### What happened?

A bug happened with the BFF
/{version}/ecoindexes/latest

### Project

Ecoindex API

### What OS do you use?

_No response_

### urls

_No response_

### Relevant log output

```shell
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `datetime` but got `str` - serialized value may not be as expected
ecoindex-api-backend | Expected `uuid` but got `str` - serialized value may not be as expected
ecoindex-api-backend | return self.serializer.to_python(
```

### Code of Conduct

- [X] I agree to follow this project's Code of Conduct

复现 BFF /{version}/ecoindexes/latest 请求，并检查该路由的 Pydantic 序列化路径和响应模型。追踪 datetime 和 UUID 值为何以字符串形式进入序列化；当端点返回预期响应且不再出现报告中的序列化警告时，即表示完成。

由索引模型根据 Issue 内容生成。