[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.

Beginne beim Dark Reader-Einstellungs-/Konfigurationsfenster, einschließlich des Firefox Android Add-ons-Einstiegspunkts, und verfolge, wie das aktuell dunkle Farbschema der Benutzeroberfläche angewendet wird. Füge eine Möglichkeit hinzu, ein kontrastreiches helles Farbschema für die Benutzeroberfläche auszuwählen, und überprüfe anschließend den Umschalter sowie die daraus resultierenden Farben auf dem beschriebenen e-ink Android-Setup.

Vom Indexierungsmodell aus dem Issue-Text verfasst.