Cancel resolver tasks if execution of an operation is terminated

### TL;DR

Would it be possible to cancel outstanding resolver tasks ~as soon as~ _before_ execution of a GraphQL operation is terminated? Outstanding / unused tasks can happen as a result of an incoercible field resolver error.

These outstanding tasks can run well after lifecycle hooks responsible for cleaning up their context have completed. As a result, they often fail and cause a lot of noisy errors for us.

### More details

Hello!

I'm coming from the `strawberry-graphql` project. We're running into a problem with abandoned resolver tasks not being cancelled, and thus failing in unpredictable ways.

Strawberry has an [extensions framework](https://strawberry.rocks/docs/guides/custom-extensions#execution-context) which allows you to wrap the execution phase of your operation processing in hooks – running code before and after execution of resolvers. We use these hooks to manage (set up and tear down) some state needed by the resolvers.

However, when a resolver of a non-nullable field fails, it may lead to the results of some other resolvers being no longer necessary. It appears that `graphql-core` will then short-circuit returning a result, while the no-longer-necessary resolvers are still running. We see that they can continue running well after the HTTP response was returned.

The problem is that Strawberry's lifecycle hooks (and I also imagine - the webserver's) would have completed by that time. As a result, we do things like terminate the DB session – making it very likely that these outstanding tasks will fail with various esoteric errors. This causes a lot of noise in our observability suite – which we'd love to avoid.

See https://github.com/strawberry-graphql/strawberry/issues/3414 for more details, and https://github.com/strawberry-graphql/strawberry/issues/3414#issuecomment-2012060461 for the comment which recommends I report the issue here.