According to the API specs for get-task-status-list, CLOUD_ACCOUNT_AGGREGATION is not a valid type to filter on. The valid values are QUARTZ, QUEUED_TASK and QPOC.
You would need to filter on the client side (which is fine since you’re using PowerShell) for the uniqueName property containing “Cloud Account Aggregation”
A big caveat to using this API
If you desire to have more than 90 rolling days of data in your report, I would suggest not using the task status API as the retention period is only 90 days
If you do not need the level of detail contained in the task-status API (accounts scanned, accounts created/updated/deleted), you can instead use the search-post API and search through events instead. You won’t get as much detail but you’ll have far more history available. It just depends on what you want.
Search Query
name:"Aggregate Source Account Failed" OR name:"Aggregate Source Account Passed"