imgpkg on OpenShift + GCP doesn't work without IMGPKG_ENABLE_IAAS_AUTH=false

**What steps did you take:**
Deploy kapp-controller on an OpenShift cluster in GCP. Or, you could spin up a local cluster that does not have access to the metadata server.

**What happened:**
The resources are not created.

**What did you expect:**
kapp-controller to get deployed successfully.

**Anything else you would like to add:**
[See this Tekton issue for a similar scenario](https://github.com/tektoncd/pipeline/issues/1742).

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