Unable to delete features owned by users that no longer exist in Portal for ArcGIS.

Additional Information

Workaround

1. Unshare the item (recommended).
2. Update the item settings by disabling the "Keep track of who created and last updated features" Editing settings.
3. Go to the Data tab in the item details and select Fields.
4. Click the "created_user" field and edit the "Editable" option in the Settings table to make the "created_user" field editable.
5. Navigate to the item details Data tab, select Table, and under the "show/hide columns" option, select the "created_user" field.
6. The "created user" field for the deleted member's features can now be updated.
7. Deleted members' features can now be deleted.
8. After the changes have been made, update the items. Editing settings to enable "Keep track of who created and last updated features" and the "Editors can only edit their own features (requires tracking)" settings. Share the item again as needed.

Steps to Reproduce