Fill empty UserIDClaim before assigning it to other values

[mdreem]

the email claim gets overridden if userIDClaim is not set.

Description

During login I am getting the error:

 Error creating session during OAuth2 callback: neither the id_token nor the profileURL set an email

Motivation and Context

It seems to be related to:
#1623
#1732

The underlying problem seems to be the code that handles Backwards Compatibility for Deprecated UserIDClaim option. it overrides the EmailClaim if they are different. But at that point the UserIDClaim is still empty, if not explicitly set and so it clears EmailClaim. Later in the code it actually is explicitly set, so I just pulled this piece of code up.
As this seems to be a workaround I am unsure about the behavior it should have and potential additional side-effects.

How Has This Been Tested?

I wrote a new test-case.

Checklist:

• My change requires a change to the documentation or CHANGELOG.
• I have updated the documentation/CHANGELOG accordingly.
• I have created a feature (non-master) branch for my PR.

[JoelSpeed]

Apologies for the delay in getting to this, but it seems like a good fix, can you add a changelog entry and I'll look to get this merged

[mdreem]

Apologies for the delay in getting to this, but it seems like a good fix, can you add a changelog entry and I'll look to get this merged

Great to hear. I added a changelog entry.

[JoelSpeed]

Thanks!