transfer_enrollment command is not properly transferring enrollment

[arslanashraf7]

Steps to Reproduce

• Register two users
• Enroll one user in a course
• Now, try to transfer this enrollment to the other user e.g.

./manage.py transfer_enrollment --from-user=<username or email>--to-user=<username or email> --run=<courseware_id>

Expected Behavior

• The enrollment gets transferred to the other user and doesn't show on the dashboard of --from-user

Actual Behavior

• The command succeeds but?
• The enrollment only gets transferred on edX, This means that the new user sees a course enrollment on edX dashboard but not on MITxOnline dashboard.
• Because this new enrollment doesn't get created in MITxOnline. It's only created on edX. Also, The previous user also sees the enrollment on both MITxOnline and edX. However, the enrollment status for the previous user is successfully set to transferred for the previous user.

Note
I noticed this issue while testing #1761, But It's worth putting some time on testing this command independently.

[pdpinch]

As far as I know, we haven't had need for this management command yet. It's more revelant in situations where we are doing a lot of B2B bulk purchases.