Exceptions occurring on Dask workers before a task starts result in a 'coroutine' object has no attribute 'type' exception in Prefect engine

[rpeden]

As of Prefect 2.6.0, exception_to_crashed_state is async and needs to be awaited, but the Dask task runner does not await it, resulting in a coroutine' object has no attribute 'type error when certain exceptions occur on a Dask worker node.

This prevents users from seeing information about the exception, making it difficult to debug and fix the error.

Will be fixed by #52.