MSC4140: support filters on delayed event lookup (#5038)
* MSC4140: support filters on delayed event lookup
Support looking up scheduled/finalised delayed events, and looking up a
single delayed event.
* Add test coverage for delayed event lookup filters
* Prettier
* Use it.each for test loop
* Support multiple delayIds
* Support single or multiple delayIds
As it may be more common to look up a single delayed event than to look
up many of them, support passing a single delayID in the lookup function
instead of needing to pass a single-element array.
