Good background homework you have done.
Stoffe made a mod, I think it was stoffe, Handmaiden's Choice?
It has been done, but it is more complicated than just that dialogue, as it changes a lot of conditionals for Atris scenes in the game.
Another option is to use KSE to change your gender to male before you enter telos academy. To do this though, you will need to keep it male, which will affect how Atton and others react to you. Switching back and forth will make a mess of things for sure!
It is known that this sort of mod has issues with TSLRCM; not sure if that is important to you but it is to most of us