Disable email notifications when importing Discussions

[renchap]

Discussions is great and more and more projects are switching to it.

Some of them are importing threads from other platforms using the API, but a big issue in doing this is spamming the repository's followers as they will receive 1 notification for each imported discussion.

For example, here is the thread about Shrine current Google Group move to Discussions: https://groups.google.com/g/sequel-talk/c/lwX2Yt3qvks
It is blocked because the maintainer (rightfully) would like to import the Google Group into Discussions, has a script to do it, but does not want to generate 10k+ Github notifications to followers.