…olcengine#1745)

### Checklist Before Starting

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### What does this PR do?

fix a bug when register async method to fsdp worker.

When use async method in fsdp worker, it fails with:
```
>                       raise value.as_instanceof_cause()
E                       ray.exceptions.RayTaskError(TypeError): ray::WorkerDict.critic_sub() (pid=232160, ip=192.168.111.50, actor_id=ca29f2b51caa8e56243d6b8e01000000, repr=<verl.single_controller.ray.base.WorkerDict object at 0x7f8c50729270>)
E                         File "/usr/local/lib/python3.10/dist-packages/ray/cloudpickle/cloudpickle.py", line 1479, in dumps
E                           cp.dump(obj)
E                         File "/usr/local/lib/python3.10/dist-packages/ray/cloudpickle/cloudpickle.py", line 1245, in dump
E                           return super().dump(obj)
E                       TypeError: cannot pickle 'coroutine' object
```
/usr/local/lib/python3.10/dist-packages/ray/_private/worker.py:919:
RayTaskError(TypeError)

You can reproduce this error in tests/ray_gpu/test_colocated_workers.py
with async method.

### High-Level Design

wrap async method if the original method is coroutine

### Specific Changes

changed _bind_workers_method_to_parent

### API

n\a

### Usage Example

tests/ray_gpu/test_colocated_workers.py


### Test

tests/ray_gpu/test_colocated_workers.py

### Additional Info.

- **Issue Number**: required by
volcengine#1721

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