Given the strong warning around the proposed customization, I think we shouldn't support this directly. Looks like not even upstream supports this without potential breakage on update. From our experience such essentially code changes cause more trouble than worth it, since from a Cloudron perspective we cannot test updates for those cases anymore.
So unless there is popular demand also from other users, I would suggest to maintain a fork of https://git.cloudron.io/packages/sogo-app which allows for this