Difficulties obtaining idToken needef for /logout endpoint

## Issue

Not sure if this is classified as a bug or I'm missing something, but in the documentation it is stated that we can only use the autorization code flow, which is fine.

But then for /logout endpoint it is stated that:

`It requires an idToken, obtained after successfully authenticating with OpenID Connect, and a URL to redirect back after the logout has been performed.`

However, I can't find any way that I can set the response_type to include the 'code id_token' for the /authorize endpoint. The default response_type gets set to 'code' and the server does not return the idToken, which I can then later use for the logout. Because of this I end up sending some invalid string for the idToken param in /logout, which creates problem for the post logout redirect and as a result I end up having to close the custom tab manually after the log out has been completed.

Please let me know if I'm missing anything with the supported logout flow.

---

## Environment

* **Your Identity Provider**: `IdentityServer 4`
* **Platform that you're experiencing the issue on**: `Android`
* **Your `react-native` Version**: `0.73.0`
* **Your `react-native-app-auth` Version**: `7.1.3`
* **Are you using Expo?**: `No`