Use the operationId as a key for ResponseFieldMapperFactory

[ansman]

This will prevent errors when wrapping subscriptions in a shared type.

This fixes #2944

[martinbonnin]

Hi 👋 ! Thanks for opening this.

One issue is that operations "could" have the same id in two different services (different schemas). Granted this is an edge case but I've seen it happen in the integration tests already. Possible solutions:

1. Wrapping each Subscription in a different class implementing ExtensibleSubscription but that doesn't scale at all (unless writing a KSP processor to generate it automatically, but I don't think we want to go that route 😆)
2. Using a Pair<Class, String> as a key, feels a bit sub-optimal but that should work
3. Removing the pool altogether.

I think 3. makes sense as the adapters are statically allocated anyways, what is cached is a thin wrapper around them that shouldn't cost much and doesn't require caching.

[ansman]

Ideally I'd want a way to pass data to the serializer built in but I'm waiting for 3.x. I removed the usage of the factory but I left if for binary compatibility reasons.

The class itself is in the internal package and can probably be removed but there are references to it in ApolloCall for example

[martinbonnin]

Thanks!