[TRI-5479] Alerts in v4 don't show the task id

[matt-aitken]

In v4 we no longer get the name of the variable you assign to a task (exportName). This is because you no longer need to export the tasks, you can have tasks that are internal to a file.

So we need to update the alerts to use the taskIdentifier instead, which is the id you set on a task.

_{From SyncLinear.com | TRI-5479}