Prerequisites

• I have checked the existing issues to ensure this is not a duplicate.
• I am running the latest version of Tailcall.

Describe the bug

Why when we query an interface existing in another GraphQL server, the query sent to the original server doesn't contain fragments?
Like that we can't query the different entities implementing the interface.
query used in tailcall:

query QueryInterface {
    queryInterface {
        name
        __typename
        ... on Author {
            author_id
        }
        ... on Book {
            book_id
        }
    }
}

query sent to the original graphql server:

INFO Query { "query": "query { Interface { name __typename author_id book_id } }" }