Hi Arimla,
From Project Settings - Field Configurations page, you can mark Expected Result field as non-mandatory.
We do support import of BDD test scenarios also. If you can please send your Zephyr Scale export file to us at help@aiotests.com, we will check it out and assist you in importing your cases in AIO Tests. You can also setup time with us via our calendar.
Regards,
Noopur