Fix skipped handler on contract register event case

[JonoPrest]

Closes #303

Need to write a test that enforces this case is handled.

Happens in the context of a batch being processed when:

1. The batch contains a contract registration
2. an event afterwards runs a contractRegister function that registers no contracts
3. Does not add the given event to the unprocessed events (which should have ended up on the arbitrary events queue)

[JonoPrest]

It's only this case that was broken before hand. So it's not super critical.

[JonoPrest]

To expand, this is not super critical. The indexers that it affects is when you have a "contractRegister" and a "handler" function for a given event.

The contracts would have still been registered as expected. It's just that the event would never be added to the unprocessed batch so it would never get a chance to run the handler.

[JonoPrest]

To be clear, it was hitting this case when the contractRegister function produced no registrations (possibly because of duplicate registration)

AND the current dynamicContratRegistrations was Some. Then it would just pass through the current registrations without adding itself to the unprocessed batch. Which we only want on the None case.

[DZakh]

Good catch 👍