fix(visitor-plugin-common): handle schema extension nodes

[ardatan]

Fixes ardatan/graphql-tools#7682

Handle schema extension nodes correctly

When a schema doesn't have an operation type defined but has schema extension definitions with directives like below,
schema extensions are not converted to schema definitions by GraphQL Tools.
So the visitor should handle schema extension nodes correctly.

Follow-up to
ardatan/graphql-tools#7685

Previously this wasn't an issue because GraphQL Tools incorrectly converted extend schema to schema.

extend schema @link(url: "https://specs.apollo.dev/federation/v2.0", import: ["@key"])

type Foo {
  id: ID! @key
  name: String
}

[changeset-bot]

🦋 Changeset detected

Latest commit: 9d9f634

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 9 packages

Name	Type
@graphql-codegen/visitor-plugin-common	Patch
@graphql-codegen/typescript-document-nodes	Patch
@graphql-codegen/gql-tag-operations	Patch
@graphql-codegen/typescript-operations	Patch
@graphql-codegen/typescript-resolvers	Patch
@graphql-codegen/typed-document-node	Patch
@graphql-codegen/typescript	Patch
@graphql-codegen/graphql-modules-preset	Patch
@graphql-codegen/client-preset	Patch

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[github-actions]

🚀 Snapshot Release (alpha)

The latest changes of this PR are available as alpha on npm (based on the declared changesets):

Package	Version	Info
@graphql-codegen/cli	6.0.2-alpha-20251112094753-9d9f6346d64d7ab7a726ad77f9cb95ebaefbfdef	npm ↗︎ unpkg ↗︎
@graphql-codegen/visitor-plugin-common	6.1.1-alpha-20251112094753-9d9f6346d64d7ab7a726ad77f9cb95ebaefbfdef	npm ↗︎ unpkg ↗︎
@graphql-codegen/typescript-document-nodes	5.0.3-alpha-20251112094753-9d9f6346d64d7ab7a726ad77f9cb95ebaefbfdef	npm ↗︎ unpkg ↗︎
@graphql-codegen/gql-tag-operations	5.0.4-alpha-20251112094753-9d9f6346d64d7ab7a726ad77f9cb95ebaefbfdef	npm ↗︎ unpkg ↗︎
@graphql-codegen/typescript-operations	5.0.3-alpha-20251112094753-9d9f6346d64d7ab7a726ad77f9cb95ebaefbfdef	npm ↗︎ unpkg ↗︎
@graphql-codegen/typescript-resolvers	5.1.1-alpha-20251112094753-9d9f6346d64d7ab7a726ad77f9cb95ebaefbfdef	npm ↗︎ unpkg ↗︎
@graphql-codegen/typed-document-node	6.1.1-alpha-20251112094753-9d9f6346d64d7ab7a726ad77f9cb95ebaefbfdef	npm ↗︎ unpkg ↗︎
@graphql-codegen/typescript	5.0.3-alpha-20251112094753-9d9f6346d64d7ab7a726ad77f9cb95ebaefbfdef	npm ↗︎ unpkg ↗︎
@graphql-codegen/client-preset	5.1.2-alpha-20251112094753-9d9f6346d64d7ab7a726ad77f9cb95ebaefbfdef	npm ↗︎ unpkg ↗︎
@graphql-codegen/graphql-modules-preset	5.0.4-alpha-20251112094753-9d9f6346d64d7ab7a726ad77f9cb95ebaefbfdef	npm ↗︎ unpkg ↗︎

[eddeee888]

Thank you!