Get Power BI embedded token using Azure/Power BI API using Postman
1. using HTTP POST request
End point URL :
https://api.powerbi.com/v1.0/myorg/groups/####group id####/reports/### report id #####/GenerateToken
2. Authorization tab in Postman

3. Headers tab in Postman

4. Body tab in Postman

By doing above you should be able to get the embedded token for the authentication code you have for the service principal.