https://linear.app/unleash/issue/2-1962/implement-new-action-events-logic
Adds a new `action_set_events` table for the new action events logic.
Even though observable events are technically immutable, we're storing
the observable event along with the action set event. This allows us to
avoid 1 join while allowing us to persist action set event information
after deleting observable events, if we wish to do so at a later stage.
