Conformance: InferencePoolInvalidEPPService Fails to Run

[danehans]

What happened:
The InferencePoolInvalidEPPService fails to run because the InferencePool manifest was not updated to reflect the latest API changes:

apiVersion: inference.networking.k8s.io/v1
kind: InferencePool
metadata:
  name: pool-with-invalid-epp
  namespace: gateway-conformance-app-backend
spec:
  selector:
    app: primary-inference-model-server
  targetPortNumber: 3000
  extensionRef:
    name: non-existent-epp-svc

What you expected to happen:
To run the test.

How to reproduce it (as minimally and precisely as possible):
Follow the steps in the conformance guide and run the test.

Anything else we need to know?:

N/A