Issue with Federation when manually adding directives

Hi. This is in context with the discussion here: https://github.com/dotansimha/graphql-code-generator/issues/3033#issuecomment-721644587

I am not sure if I am doing something wrong here. I have my directives added manually to support VSCode GraphQL extension (since it does not support Apollo Federaton: graphql/graphiql#2351) like this:

```gql
scalar _Any
scalar _FieldSet

# a union of all types that use the @key directive
union _Entity

type _Service {
sdl: String
}

extend type Query {
_entities(representations: [_Any!]!): [_Entity]!
_service: _Service!
}

directive @external on FIELD_DEFINITION
directive @requires(fields: _FieldSet!) on FIELD_DEFINITION
directive @provides(fields: _FieldSet!) on FIELD_DEFINITION
directive @key(fields: _FieldSet!) on OBJECT | INTERFACE

# this is an optional directive discussed below
directive @extends on OBJECT | INTERFACE
```

Now, the VSCode GraphQL extension works well after these directives are added.

If I run the codegen now, it runs but I see issues in generated types.

**With directives added manually:**

**Without directives:**

The error thrown: `Generic type 'DeepPartial' requires 1 type argument(s).`

The new types get added when I add the directives manually but not when I don't.

Now, if I try to exclude the directives from the codegen (since `federation:true` is already added) like this (Fed.gql contains the directives manually added):

```yml
schema:
- './packages/modules/**/schema/**/*.gql'
- ${GLOBAL_GQL_URL:http://g.lvh.me:2500/graphql}
- "!(packages/modules/**/schema/**/Fed.gql)"
```

I get the issue which I reported here: https://github.com/dotansimha/graphql-code-generator/issues/5013

Hope this clarifies.

**PS:** I am working on moving towards schema stitching and this might not be an issue for me over the long run. But may still be relevant for others.

**CC:** @dotansimha