Changes the type used by the useEventSearch hook to be `EventSchema`
from OpenAPI instead. This is more accurate with what we're actually
getting. And crucially for the event log search, it contains the
`createdByUserId` property that we need to filter out events.
It's mostly a straightforward find and replace except for one instance
where we need to do some extra fiddling. There's an inline comment
explaining that.
