fix(jans-casa): account linking not working

1. Account link configured
2. Github and Google authenticator configured
3. Initial enrolment ( first login ) working okay
4. From second login, "jans-auth" unable to find linked user. 
5. Flex v5.5.0

Screenshot with error ( from jans-auth ) attached below: 

<img width="1710" alt="Image" src="https://github.com/user-attachments/assets/975a0505-6960-4838-8847-7963194ae51e" />