Firewall breaks `drush cache:rebuild` on Drupal 8

Running drush cache:rebuild with firewall enabled returns:

In DAO.php line 1683:
                         
  is not of type String  
                         

The issue is the call to CRM_Utils_System::ipAddress(), which isn't populated when running from the CLI. Since most CLI commands don't run firewall code it's fine, but a cache clear does.

I'll send an MR that fixes this.