I'm sorry, but I couldn't find the exact roles required for Azure Container Instances (ACI) in the Prefect documentation. However, typically, you would need roles that allow you to manage container instances, such as creating, running, and deleting them.
In Azure, you might want to consider roles like "Contributor" or "Owner" at the resource group level, or specific roles related to Azure Container Instances if they exist. Please note that these roles should be assigned carefully considering the principle of least privilege.
For the most accurate information, I would recommend checking the Azure documentation or reaching out to Azure support.