Apparently DISALLOW_FILE_MODS really doesn't play nice with the download link in GU endpoint

Apparently with the `DISALLOW_FILE_MODS` constant set from #17 this seems to block the Git Updater endpoint from passing a download_link resulting in the FAIR plugin being unable to update. Not a good look.

I assume we'll need to revert #17 and figure out something else here.

https://fair.slack.com/archives/C092THESN4F/p1754265061763779