Add support for outputLatency with audio worklets

[FrancoisRecisio]

Hello! I was wondering if it would be possible to access audio latency via emscripten, I guess so?

https://developer.mozilla.org/en-US/docs/Web/API/AudioContext/outputLatency

I might take a look at it one day, if it's not too complicated to implement.

[cwoffenden]

It's part of the changes I'd like to make (conversation started in #22949). I'd like to add a filled struct with number of samples, sample rate and latency (and then anything else as the API grows).