Test events

[plaintextpaco]

We have forgotten to add/modify events and broken the subgraph in the past, as shown by PR #23 , so it's important that we test the appropiate events are emmited so these kind of errors don't bubble that far up and break this repo's CI instead.

I think the most appropiate thing will be to test them in hardhat, since I believe it's easier to assert event emmisions than in foundry.