hypershift e2e and conformance for 4.15 and 4.14 clusters under tests are failing due to version skew with the mgmt cluster version (4.16).

As of 4.16.0-rc3, openshift-controller-manager switched to using bound service account tokens in https://issues.redhat.com/browse/API-1644

Two PRs were made against openshift/origin and openshift/library-go to support this for 4.16.

https://github.com/openshift/origin/pull/28679
https://github.com/openshift/library-go/pull/1697

However, for 4.15 and 4.14 tests, both repos do not have those changes. The changes might not be backward compatible (need feedback from lusanche@redhat.com on this).

In o/o for example, it is using 4.15 o/o code to do prom operation on a 4.16 mgmt cluster.
https://github.com/openshift/origin/blob/2320880deab4c456c7d8b157ea7dc91b85c85302/test/extended/etcd/leader_changes.go#L32