Remove dependency on edx-enterprise

[arbrandes]

In trying to include the AuthN MFE in the Tutor release of Olive, we found that the login API used by this MFE requires edx-enterprise to be deployed and configured, so that even if DISABLE_ENTERPRISE_LOGIN is set to true in the MFE, logins cannot work without it.

It should be possible to use this MFE without the edx-enterprise requirement.

[arbrandes]

@zainab-amir, can you confirm there's no way around the edx-enterprise requirement?

[arbrandes]

As @zainab-amir kindly noted in the Olive Matrix, enterprise support is in fact optional, because the function pointed out in the description is wrapped by enterprise.is_enabled.

While in my previous tests the function was in fact being called - and failing - it turns out that it was a red herring. For some reason, probably related to a CSRF issue in Tutor, even though enterprise was definitely not enabled, the wrapper for some reason thought it was. After fixing the above issue, the problem went away.

Closing, with apologies for the noise.