Trigger Power BI dataset refresh from Flow using service principal

Hi 

I have set up Flow Custom connector to trigger dataset refresh , it works fine using my network id. Followed below link

https://community.powerbi.com/t5/Community-Blog/Refresh-Power-BI-dataset-with-Microsoft-Flow-by-Konstantinos/ba-p/622941

But would like to use service principal from Flow to trigger the refresh instead of my network id. Created service principal and added to Power BI workspace. Would like to know how to use service principal in Flow Custom connector or Http action to make REST API Calls. In "New connection option" there is no option to choose service principal, always prompts for my Azure AD network id. Could not find any information on this. Please let me know how to do this. Thanks!

Service principal:

https://docs.microsoft.com/en-us/power-bi/developer/register-app

https://docs.microsoft.com/en-us/power-bi/developer/embed-service-principal#how-to-get-the-service-principal-object-id