[React Query] addInfiniteQuery option imports QueryFunctionContext without usage

Hi there! I've been having lots of success with code generation using the React Query plugin.

Was adding the `addInfiniteQuery` option into my `codegen.yml` file, and noticed that it imports `QueryFunctionContext` from `react-query` unnecessarily according to my configuration. This sets off my ESLint rules, and I'm currently having to remove the import manually before committing any code.

The line in question is here: https://github.com/dotansimha/graphql-code-generator/blob/master/packages/plugins/typescript/react-query/src/visitor.ts

I've provided my `codegen.yml` below – perhaps it is an issue of my custom fetching function? Happy to push up a PR to resolve this.

```yaml
overwrite: true
schema: "http://localhost:4000/v1/graph"
documents: "graphql/**/index.ts"
generates:
graphql/generated.ts:
plugins:
- "typescript"
- "typescript-operations"
- "typescript-react-query"
config:
addInfiniteQuery: true
exposeFetcher: true
exposeMutationKeys: true
exposeQueryKeys: true
fetcher:
func: ../utils/gql-fetch#gqlFetch
fetchParams:
headers:
Content-Type: application/json
maybeValue: T
hooks:
afterOneFileWrite:
- prettier --write
```

Start in packages/plugins/typescript/react-query/src/visitor.ts and inspect how addInfiniteQuery generates imports when a custom fetcher is configured. Reproduce the supplied codegen.yml configuration, then verify generated output no longer includes an unused QueryFunctionContext import and remains valid under ESLint.

Written by the indexing model from the issue text.