PartitionChannel和DynamicPartitionChannel支持thrift

**Is your feature request related to a problem? (你需要的功能是否与某个问题有关?)**
PartitionChannel和DynamicPartitionChannel支持thrift。
我使用上面两种channle，但是会报错：ThriftFramedMessage does not support MergeFrom，
1、然后我根据文档准备重写ResponseMerger的Merge接口，但是发现只提供了protobuf版本的接口。
2、DynamicPartitionChannel的AddChannel并没有加载用户实现的ResponseMerger，只有PartitionChannel实现了。

**Describe the solution you'd like (描述你期望的解决方法)**
PartitionChannel和DynamicPartitionChannel支持thrift。

**Describe alternatives you've considered (描述你想到的折衷方案)**
提供接口允许自定义ResponseMerger，并且在DynamicPartitionChannel生效。

**Additional context/screenshots (更多上下文/截图)**

Start by reading the documented ResponseMerger interface and the implementations of PartitionChannel and DynamicPartitionChannel, focusing on AddChannel and the ThriftFramedMessage error. The work is complete when both channel types support thrift and DynamicPartitionChannel applies a user-provided ResponseMerger, including the required merger interface changes.

Written by the indexing model from the issue text.