Duplicated 'DocumentNode' import with 'typescript-generic-sdk'

### Which packages are impacted by your issue?

`typescript-generic-sdk`

### Describe the bug

Duplicated `DocumentNode` import when `rawRequest` is setted to `true` and `documentMode` is setted to `documentNode`

### Your Example Website or App

https://noexample.com

### Steps to Reproduce the Bug or Issue

Run `graphql-codegen`

### Expected behavior

`DocumentNode` imported once

### Screenshots or Videos

_No response_

### Platform

- OS: Linux
- NodeJS: 18.16.1
- `graphql` version: 15.6.1
- `@graphql-codegen/typescript-generic-sdk` version: 3.1.0

### Codegen Config File

```yaml
schema: schema.graphql
documents: document.graphql
generates:
types.ts:
plugins:
- typescript
- typescript-operations
- typescript-generic-sdk
config:
rawRequest: true
documentMode: documentNode
```

### Additional context

_No response_