[bug] InformerController Retries Continue on `nil` Responses

[Austin Pond]

When the operator.InformerController queues up a retry for a failed Add/Update/Delete Watcher event, the retry ticker process will re-execute the appropriate handler with the original information after the RetryPolicy duration has elapsed. If the handler function returns an error again, it will re-queue after the new duration, and update the retry counter that it passes to the RetryPolicy func. However, if the handler function returns nil, the queued retry is not removed from the list, and the counter is not incremented, causing it to be retried indefinitely using the interval of the first retry.