Add Microsoft.PowerBIDedicated/capacities/write permission to client application?

[ljt5]

Hi, I want to use the Azure REST API to update the capacity of a Power BI Embedded using the API. I want to use this endpoint:

PATCH:  https://management.azure.com/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/provi...

Info here: https://learn.microsoft.com/en-us/rest/api/power-bi-embedded/capacities/update?tabs=HTTP

The problem is I'm getting the following error message: 

The client 'xxx' with object id 'xxx' does not have authorization to perform action 'Microsoft.PowerBIDedicated/capacities/write' over scope '/subscriptions/xxx' or the scope is invalid. If access was recently granted, please refresh your credentials.

I have created a Client Application and added it with role Contributor to the PowerBI Embedded resource. I can use other endponts of the PowerBI Embedded Capacities API that require read permission but not this one.

I have also tried to add the application to the PowerBI Capacity Administrators in the Azure Portal but still no write permission. How can I give Microsoft.PowerBIDedicated/capacities/write permission to the client app? Thx