Observability task: add a collection to the MigrationInvoker to judge the actual usage of the current request

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

## Describe the proposal

EN: Observability task: add a collection to the MigrationInvoker to judge the actual usage of the current request'

中文：可观测性任务：在 MigrationInvoker 那里加个采集,判断目前请求的实际使用方式的,方便查看当前迁移过程中的注册模式分布情况

Start at the MigrationInvoker entry point and trace how the current request’s actual usage is represented during migration. Done means a collection reports the distribution of registration modes used by requests, with the behavior verified in the relevant migration path.

Written by the indexing model from the issue text.