Flaky e2e tests

[ashish-amarnath]

What steps did you take and what happened:
Velero E2E tests have non-deterministic waits/sleep that can cause the tests to occasionally produce false negatives.
We should use conditional waiting instead of non-deterministic waits to obtain more consistent test results.

What did you expect to happen:

The output of the following commands will help us better understand what's going on:
(Pasting long output into a GitHub gist or other pastebin is fine.)

• kubectl logs deployment/velero -n velero
• velero backup describe <backupname> or kubectl get backup/<backupname> -n velero -o yaml
• velero backup logs <backupname>
• velero restore describe <restorename> or kubectl get restore/<restorename> -n velero -o yaml
• velero restore logs <restorename>

Anything else you would like to add:
[Miscellaneous information that will assist in solving the issue.]

Environment:

• Velero version (use velero version):
• Velero features (use velero client config get features):
• Kubernetes version (use kubectl version):
• Kubernetes installer & version:
• Cloud provider or hardware configuration:
• OS (e.g. from /etc/os-release):

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[ashish-amarnath]

PR #3527 addresses the flake in the kibishii_tests

[codegold79]

@ashish-amarnath, PR #3564 that fixes the API group versions e2e tests is ready to review.