Fix coroutine serialization error in PowerBIDatasetRefreshOperator

[henry3260]

Why

When the PowerBIDatasetRefreshOperator is executed with wait_for_completion=False, it takes the synchronous "fire-and-forget" path. However, the underlying hook method trigger_dataset_refresh is an async function.

What

Forced Synchronous Execution: Wrapped the hook.trigger_dataset_refresh(...) call with asyncio.run(...) inside the wait_for_completion=False block. This ensures the async hook method executes fully within the current synchronous thread and returns the actual string ID.

closes: #63811

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[henry3260]

cc @morelgeorge

[SameerMesiah97]

I think you found the cause but I feel the fix might be at the wrong layer. Also, did you manage to reproduce the bug locally?

[henry3260]

I think you found the cause but I feel the fix might be at the wrong layer. Also, did you manage to reproduce the bug locally?

Thanks for reviewing! Yes, I reproduced the error locally with the unit test.