"Detect dark theme" button not present in settings

### Prerequisites

- [X] I [searched for any existing report](https://github.com/darkreader/darkreader/issues?q=is%3Aissue) about this bug to avoid opening a duplicate.
- [X] I can reproduce this bug in a new, unmodified web browser profile with Dark Reader installed as the only extension.
- [X] I understand I need to use the [Broken Website Report template](https://github.com/darkreader/darkreader/issues/new?assignees=&labels=Broken+Website&template=broken-website-report.yml&title=%5BBroken+Website%5D+Replace+with+title) if this bug I am reporting occurs on a single website.

### Bug Description

This feature has been listed since March 2022 (https://darkreader.org/blog/detect-dark-theme/) however I was never able to find the "Detect dark theme" button illustrated at the above page.

I activated "v5 design preview" as instructed, and when I click Settings it tells me I'm on Version 5 Preview (4.9.43) but there is no trace of the "Detect dark theme" button.


According to the blog article linked above this is where the button should appear.
However I also looked for it in every menu and submenu.

This has been driving me mad for months now, please tell me where I can find it or what I am doing wrong.

Thank you.

### Website Address

not applicable

### Steps To Reproduce

See bug description.

### Expected Behavior

See bug description.

### Actual Behavior

See bug description.

### Screenshots

_No response_

### Operating System

Windows 10

### Web Browser name and version

Brave 1.48.171 - Chromium: 110.0.5481.177 - 64 bit

### Dark Reader version

4.9.43

### Additional Context

_No response_