I'm not sure if i'm going about this correctly but under the concept of removing the line we don't need I have tried following the instructions from https://github.com/osTicket/osTicket-plugins but I'm having some issues.
I have downloaded the repo, successfully hydrated, then modified the oauth2.php to comment out line 640. I then ran the build command and it has given me an auth-oauth2.phar. I have copied this into my includes/plugin folder and successfully activated it in osTicket however when I then go to configure the authentication the popup box containing all the IDP info is just blank.