OPENSHIFT_IMG_OVERRIDES is not retaining the mirroring order from ICSP/IDMS

The environment variable OPENSHIFT_IMG_OVERRIDES is not retaining the order of mirrors listed under a source compared to the original mirror/source listing in the ICSP/IDMSs.

Every time

1. Setup a mgmt cluster with either an ICSP like:

  apiVersion: operator.openshift.io/v1alpha1
  kind: ImageContentSourcePolicy
  metadata:
    name: image-policy-39
  spec:
    repositoryDigestMirrors:
    - mirrors:
      - quay.io/openshift-release-dev/ocp-release
      - pull.q1w2.quay.rhcloud.com/openshift-release-dev/ocp-release
      source: quay.io/openshift-release-dev/ocp-release

2. Create a Hosted Cluster

Nodes cannot join the cluster because ignition cannot be generated

Nodes can join the cluster

Issue is most likely coming from here - https://github.com/openshift/hypershift/blob/dce6f51355317173be6bc525edfe059572c07690/support/util/util.go#L224