Allow callers to filter events by subscription ID

[zomglings]

Currently, as an example, callers can only filter ethereum_blockchain events using addresses.

IT would be a good idea to also allow them to filter using subscription IDs. This was suggested by kdowney in Discord: https://discord.com/channels/867156607644860418/867156608118947864/908460170940653568

It would be useful for users who are programmatically generating subscriptions.