refactor(core): Refactor hasNext/stale on OperationResult to be required

[kitten]

Summary

Since OperationResult.hasNext is now important to determine whether operations should be deduplicated (as before, to be fair), and OperationResult.stale is important for toPromise to find the right result, it's a little dangerous not to have them be required.

Hence, the thinking here is to make them required and to ensure that for @defer/@stream we won't run into cases where those never reset to false or where deferred/streamed responses are duplicated.

Set of changes

• Update hasNext and stale to be required
• Update tests and types