Can't identify backed up entity from Recovery Service Activity Logs

**Background:** We are evaluating ways to make Azure logs more useful in our platform, and are currently looking at some use cases around Azure Recovery Service Vaults. Specifically, there is an activity log that indicates when a Recovery Service backup job is completed that would be useful. However, when referencing the entity that was backed up, it only provides the entity name. This is not enough to be uniquely identifiable- [we also need the resource group](https://docs.microsoft.com/en-us/azure/azure-resource-manager/management/resource-name-rules#microsoftcompute).

**Request:** We'd like have the resource group and/or the full resource_id of the backed up entity added to the Activity Log generated from Azure Recovery Service backups. This will allow us to do some helpful correlation/tagging automatically in Datadog that solves some customer use cases.

category: Administrative
eventName: AzureBackupActivityLog
operation name: Microsoft.RecoveryServices/vaults/backupFabrics/protectionContainers/protectedItems/backup/action

**Note**: While there are Recovery Service resource logs we could use to get this information, we want to implement this based on activity logs since they are significantly simpler to configure and manage.

Start by locating the AzureBackupActivityLog definition and the specification for Microsoft.RecoveryServices/vaults/backupFabrics/protectionContainers/protectedItems/backup/action. Review the related Recovery Service activity-log schema and comments for the supported API version. Done means the activity log exposes the backed-up entity's resource group or full resource_id for reliable correlation.

Written by the indexing model from the issue text.