Show email as fallback

There's an issue where the name fields are not being populated in the
DSI oauth payload, as a temporary fix display the email address of the
DFE sign in user who verified the claim

app/models/policies/further_education_payments/admin_tasks_presenter.rb

@@ -14,7 +14,7 @@ def provider_verification
       end
 
       def provider_name
-        [verifier.fetch("first_name"), verifier.fetch("last_name")].join(" ")
+        [verifier.fetch("first_name"), verifier.fetch("last_name")].join(" ").presence || verifier.fetch("email")
       end
 
       def provider_verification_submitted?