APIServerSource EventTypes created once per namespace, not per source

[Cali0707]

Describe the bug
When there are more than one APIServerSource deployed to the same namespace, it seems like the eventtypes which are created by the duck reconciler only show up for one of the sources.

Expected behavior
Each APIServerSource should create 3 eventtypes, regardless of whether or not there already is an APIServerSource in the same namespace

To Reproduce
To reproduce, run:

SYSTEM_NAMESPACE=knative-eventing go test -v -count=1 -tags=e2e -run ApiServerSourceDataPlane_SinkTypes -timeout=8m ./test/rekt

This test creates three APIServerSources in one namespace, so you would expect to get 9 eventtypes created (each source creates 3). However, only one set of eventtypes is created.

Knative release version

Additional context
Add any other context about the problem here such as proposed priority