Use subject as a fallback for unique id.
Use subject as a fallback for unique id.

AzureAD/microsoft-authentication-library-for-objc,AzureAD/microsoft-authentication-library-for-objc,AzureAD/microsoft-authentication-library-for-objc,AzureAD/microsoft-authentication-library-for-objc,AzureAD/microsoft-authentication-library-for-objc