Description

Removes all custom CRD upgrade pre-flight check validations in favor of importing validation logic from kubernetes-sigs/crdify.

This allows OLM to stay consistent with what is deemed "safe" by an more formal library that performs validation checks. As was the previous behavior, OLM configures the validation to be as strict as reasonably possible and to continue failing closed on unhandled changes.

While it is still possible to implement custom validations with this approach (by adding them to the registry), it would be awesome to see OLM maintainers get involved in discussions with the maintainers of kubernetes-sigs/crdify and contribute new validations there first and pull them in through dependency updates.

Reviewer Checklist

• API Go Documentation
• Tests: Unit Tests (and E2E Tests, if appropriate)
• Comprehensive Commit Messages
• Links to related GitHub Issue(s)