java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.String

- [ ] I have searched the [issues](https://github.com/apache/dubbo/issues) of this repository and believe that this is not a duplicate.

### Environment

* Dubbo version: 2.7.3
* Operating System version: xxx
* Java version: xxx

### Steps to reproduce this issue

1. 编写request

public class xxxxxxRequest implements Serializable {
private static final long serialVersionUID = 1L;
private List ids;
}
泛化调用
"request": {
"ids": [1]
}
2. 
4. 

Pls. provide [GitHub address] to reproduce this issue.

### Expected Behavior
正确的抛出类型转换错误而不是在调用for循环的时候抛类型转换错误

### Actual Behavior

If there is an exception, please attach the exception trace:

```
Just put your stack trace here!
```

Start by reproducing the generic invocation with a request whose ids field is List but whose input contains the integer 1. Trace where deserialization or type conversion occurs before the for loop; done means the type-conversion error is raised at the correct boundary rather than during iteration.

Written by the indexing model from the issue text.