Avoid BindableEvent in Brio

[OttoHatt]

A brio will create a BindableEvent if its :GetDiedSignal() method is used. This is slower than instantiating an optimised Lua reimplementation. It's also worth noting that brios typically only have 1 listener to their died signal (an observable subscription via :ToMaid()), so an implementation optimised for only one listener (i.e. GoodSignal using a linked list) is preferable.