Incorrect name for FieldSet scalar in Federation v2

[dariuszkuc]

Library Version 6.1.0

Describe the bug Federation v1 defined scalar as _FieldSet. Federation v2 introduced namespacing of the federated definintions (defaults to federation__ unless explicitly imported through @link directive) and in order to avoid ___ (3 underscores) _FieldSet scalar was renamed to a FieldSet.

It appears that composition logic accepts both _FieldSet and FieldSet so it is not a critical issue but should be fixed in the next major release (it is a breaking change).

To Reproduce See https://github.com/ExpediaGroup/graphql-kotlin/blob/master/generator/graphql-kotlin-federation/src/test/kotlin/com/expediagroup/graphql/generator/federation/FederatedSchemaV2GeneratorTest.kt

Expected behavior Federation v1 schema should define the scalar as _FieldSet Federation v2 schema should define the scalar as FieldSet