[4.0] Emit an error if the link chain does not emit any values for queries or mutations #12482
Description
When the link chain only emits a complete notification without first emitting a value, this is problematic and likely a bug. Unfortunately the client does not handle this well so you'll get some difficult errors. We should instead detect this and emit an error specifying that a value should be emitted.
This should only apply to queries and mutations since subscriptions are fine to start the connection and never emit anything before closing.