[Feature Request] Provide a light mode for the Dark Reader interface itself

# Feature Request

I'm requesting a light mode toggle for the Dark Reader interface itself. That is, when using the preferences / configuration window of Dark Reader (e.g., by navigating in Firefox Android to Add Ons -> Dark Reader), being able to set the UI to a dark text on light background mode. My preference would be solid black / solid white (#000 / #fff) respectively.

## Is this feature request related to a problem?

The dark scheme used by the Dark Reader configuration interface is difficult to read on e-ink devices. Offering an alternative light scheme would address this issue.

## Screenshots

## Additional Context

I have an e-ink Android device and use Firefox/Android (Fennec/Android from F-Droid) as my principle browser.

The device itself is an Onyx BOOX Max Lumi using a 13.3 E-Ink display at 1650x2200 resolution, 207 ppi, 16-shade greyscale. The display is principally reflective rather than emissive, with a "frontlight" that may be activated in low-light conditions.

E-ink is a non-emissive display technology. Generally, dark text on light background is far more readable than light on dark. Greyscale rendering is also limited, with high-end displays offering 16 shades, and many less. High-contrast light schemes are both easier to read and subjectively easier on the eyes than light-on-dark.

Dark Reader is successful at forcing light modes on many websites. (One such example is my Mastodon account at https://toot.cat.)

However the Dark Reader interface itself remains in dark mode, which is difficult to read.

Thanks.