Check versioned and unversioned pollers in certain cases

[carlydf]

What was changed

1. Check unversioned pollers for the target version if the current version is nil and strategy is progressive
2. Check versioned pollers for Drained versions if the controller is not running a k8s Deployment for that version

Why?

1. So that we can still respect Progressive rollout steps if Current Version is nil and we confirm unversioned pollers for all Target Version task queues
2. So that we can only block rollout of a new version if we have a pathological # of ineligible for delete versions, meaning in most cases, users can rely on the server to delete their old versions.

Checklist

1. Closes

2. How was this tested:

• Unit test for maxVersionsIneligibleForDeletion
• Integration test where Progressive strategy is respected when unversioned pollers exist
• Integration test where deployment is at max versions ineligible and controller doesn't roll out new deployment
• Integration test where deployment has max versions but they are eligible for deletion so controller does roll out new deployment

4. Any docs updates needed?