request_func for remove_from_load_balancer (and friends)

- [x] Mangle `supervisor.SupervisorService`
- [x] Mangle `launch_server_v1.delete_server`
- [x] Mangle `launch_server_v1.remove_from_load_balancer`
I find this quite confusing as well, because heck if I can remember what C4 does for a given class hierarchy while I'm working on it, but I defer to [James Knight's somewhat ranty (but at least correct) explanation](https://fuhm.net/super-harmful/).