Field resolver validation reports a false positive for array and object types

# Problem
Given the following schema
```
schema {
query: Query
}

type Query {
someField: TypedField
}

type TypedField {
one: String!
two: String!
}
```

Where the schema is mapped using
```
$registry->addFieldResolver('Query', 'someField'
$builder->fromValue(['one' => 1, 'two' => 2])
);
```

The TypedField will automatically be resolved by the GraphQL library's `Executor::defaultFieldResolver`. However, the validator is not aware of this and will report missing field resolvers for the sub-types, even though the schema will work just fine.

This can lead to bug reports which may put people on the wrong trail such as https://www.drupal.org/project/graphql_address/issues/3354352

# Proposed resolution
This is a tricky problem because the schema can not be validated at inspection time, but really only by inspecting the resolved value. The current mapping validation mostly checks "if there's a field resolver" and doesn't capture any information about the resolvers, so we also can't utilise something like reflection to make this process smarter and look at the `@return` type of ` Resolver::resolve` method (this would require also inspecting the output of the `ResolverBuilder`'s chain).

This would be a good candidate for the providing module to mark the type `TypedField` as an ignored type. The Validator already has an `$ignored_types` optional argument which would need to be provided in the [`ValidationController`](https://github.com/drupal-graphql/graphql/blob/8.x-4.x/src/Controller/ValidationController.php#L92).

The downside is that if someone uses a different resolver for the `someField` then it may no longer return a type which actually has the `one` and `two` fields. However this will not be caught by the validator because it's ignored.