Add Webhook Support for Dataset Refresh Completion

I currently trigger my dataset refreshes using the Power BI REST API. However, to avoid overwhelming the system, I can't refresh all reports at the same time. This means I have to constantly poll the API to check the refresh status of each dataset before triggering more.

This approach isn't efficient and puts unnecessary load on both the client and the Power BI service. It would be much better if we had the option to configure a webhook that notifies us when a dataset refresh is completed. That way, we could trigger subsequent refreshes or downstream processes only when needed—without continuous API calls.

Please consider adding webhook support for dataset refresh completion events!