Revert "base: ensure migrated persons have a user_id"

This reverts commit bc67c2c4.

This is seem to stall testFunctionalAdvancedECommerce with this error:

      Module script, line 5, in Workflow_ensureUserId
       - <PythonScript at /erp5_portal_7f1517681f85de9695ca475d69c4d66f/portal_workflow/login_interaction_workflow/scripts/Workflow_ensureUserId>
       - Line 5
        user = state_change['object'].getParentValue()
      Module AccessControl.ZopeGuards, line 87, in guarded_getitem
        if getSecurityManager().validate(object, object, None, v):
    Unauthorized: You are not allowed to access '2' in this context

let's revert for now, we'll re-do this with more tests.