Event type v1b3 still does default broker for unset reference

[matzew]

Applying this:

apiVersion: eventing.knative.dev/v1beta3
kind: EventType
metadata:
  name: dev.knative.source.github.push-v1b3
  namespace: default
spec:
  attributes:
    - name: type
      value: dev.knative.source.github.push
      required: true
    - name: specversion
      value: "1.0"
    - name: myextension
      value: "foo"
    - name: source
      value: "https://github.com/knative/eventing"

results in this:

apiVersion: eventing.knative.dev/v1beta3
kind: EventType
metadata:
  annotations:
    eventing.knative.dev/creator: kubernetes-admin
    eventing.knative.dev/lastModifier: kubernetes-admin
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"eventing.knative.dev/v1beta3","kind":"EventType","metadata":{"annotations":{},"name":"dev.knative.source.github.push-v1b3","namespace":"default"},"spec":{"attributes":[{"name":"type","required":true,"value":"dev.knative.source.github.push"},{"name":"specversion","value":"1.0"},{"name":"myextension","value":"foo"},{"name":"source","value":"https://github.com/knative/eventing"}]}}
  creationTimestamp: "2024-06-27T11:48:06Z"
  generation: 1
  name: dev.knative.source.github.push-v1b3
  namespace: default
  resourceVersion: "5993"
  uid: 7b88e227-89bd-49de-8be5-ac9d459006c2
spec:
  attributes:
  - name: type
    required: true
    value: dev.knative.source.github.push
  - name: source
    required: true
    value: https://github.com/knative/eventing
  reference:
    apiVersion: eventing.knative.dev/v1
    kind: Broker
    name: default
    namespace: default
status: {}