[Documentation] Example for creating an ACR service connection using configuration file

In the effort to automate the deletion and creation of ACR service endpoint, I've had hard time figuring out the following behaviors of the creation and removal of a service endpoint:

An app registration and service principal (as well as a role assignment) is created automatically upon creation of the service endpoint for ACR Container Registry
When the service endpoint is deleted, the app registration / service principal and role assignment associated with that service endpoint don't get cleaned up

Issue reference from azure cli extension repo - https://github.com/Azure/azure-cli-extensions/issues/1497

Would be best to include an example in both az devops sevice-endpoint command example and https://docs.microsoft.com/en-us/azure/devops/cli/service_endpoint?view=azure-devops