This should be the final stack in the entire roles project. This is the client-side logic for `web` to handle role deletion. Per the designs, the warning message is the same as on `native`, with
either a generic deletion message if nobody is assigned the role or a more specific one if members have this custom role.
cc @ashoat to sign off on the copy on `web`
[[ https://linear.app/comm/issue/ENG-4432/create-the-modals-that-will-allow-the-user-to-confirm-role-deletion | ENG-4432 ]]
Depends on D8624