Disable or remove listener optimization that can cause listeners to not be triggered

[davidreis97]

Since this improvement we've had issues with listeners not being triggered, especially when working on localhost where we frequently FLUSHALL our local databases, which removes the key that keeps track of whether there are any listeners for a particular data structure.

We use listeners a lot and while we have not seen any performance benefit to this optimization, its caused us some trouble as described, so we would see a lot of benefit if we could have an option to disable this optimization and send listener events unconditionally.