fix how imageReferences is injected in checkimages clusterPolicy

Fix the recent MR : !828 (merged)

Error message is :

2024/10/11 07:30:10.905960 Kustomization/kyverno-policies state changed: 
BuildFailed - kustomize build failed: 
replace operation does not apply: 
doc is missing path: /spec/rules/0/verifyImages/0/imageReferences: 
missing value