MFA not requested during onboarding for SSO users

**Describe the bug**
An user use the public proxy for enrollment with external SSO. He will not be requested to set up the MFA during the registration process (despite having all locations requiring MFA).

At the opposite, a user that get enrolled without SSO will be requested to set up the MFA during enrollment.

**To Reproduce**
Steps to reproduce the behavior:
1. Having an external SSO set up (Google in our case)
2. The user is starting the enrollment in the public proxy (and may continue the enrollment in the Client, both results to the same)
3. The enrollment steps are not requesting him to set up the MFA. He will need to manually edit his account (supposing the user is given an access to the Core).

**Expected behavior**
Users signing up with SSO should have the same MFA restrictions during enrollment than users registering without SSO.

**Version information**
- Defguard Core version: v1.5.0