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- [ ] 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: 2.7.18
* Operating System version: macos
* Java version: 1.8

### Steps to reproduce this issue

1. 服务端采用dubbo泛化实现方式，服务端直接返回map类型的响应对象，响应对象中有list集合，list中返回的数据为map结构
2. 客户端正常调用，收到的响应数据list中的map结构没有转换为接口定义的实际java对象，导致程序做进一步处理报错
3. 经验证3.1.1 版本仍然存在该问题
4. 经排查后出问题的类为DecodeableRpcResult，代码段如下：
<img width="768" alt="image" src="https://user-images.githubusercontent.com/12338948/199507015-8b9ca5ed-17c6-475f-9190-6cf021f2dbea.png">
<img width="1115" alt="image" src="https://user-images.githubusercontent.com/12338948/199507116-9adc85b7-14c9-47c9-9b53-f94eec2f33c2.png">


Pls. provide [GitHub address] to reproduce this issue.
https://github.com/iloveoovo/dubbo-genericimpl-issue

### Expected Behavior

consumer端能正常反序列化

### Actual Behavior
consumer 端对于响应参数字段中List 字段的泛型处理错误

<T> T readObject(Class<T> cls, Type type) throws IOException, ClassNotFoundException;
    /**
     * The following methods are customized for the requirement of Dubbo's RPC protocol implementation. Legacy protocol
     * implementation will try to write Map, Throwable and Null value directly to the stream, which does not meet the
     * restrictions of all serialization protocols.
     *
     * <p>
     * See how ProtobufSerialization, KryoSerialization implemented these methods for more details.
     * <p>
     * <p>
     * The binding of RPC protocol and biz serialization protocol is not a good practice. Encoding of RPC protocol
     * should be highly independent and portable, easy to cross platforms and languages, for example, like the http headers,
     * restricting the content of headers / attachments to Ascii strings and uses ISO_8859_1 to encode them.
     * https://tools.ietf.org/html/rfc7540#section-8.1.2
     */
    default Throwable readThrowable() throws IOException, ClassNotFoundException {
        Object obj = readObject();
        if (!(obj instanceof Throwable)) {
            throw new IOException("Response data error, expect Throwable, but get " + obj);
        }
        return (Throwable) obj;
    }
    default Object readEvent() throws IOException, ClassNotFoundException {
        return readObject();
    }
    default Map<String, Object> readAttachments() throws IOException, ClassNotFoundException {
        return readObject(Map.class);
    }
}