Remove dependency on browser_style: true

[tdulcet]

As of Firefox 118, support for browser_style: true was removed from Manifest V3. This library should include any CSS needed to follow the Firefox/Thunderbird Photon design locally. See the migration guide on MDN for more information. Also see this comment on BMO for more details on what specific styles were removed and their effect.

This would be needed for TinyWebEx/common#14.

[rugk]

Yeah AFAIK/IIRC the dependency is not large, it is mostly the style of the controls and IIRC the style of the (reset) button was so flat that I never used it for that.

Actually I also found rugk/offline-qr-code#44 and rugk/offline-qr-code#97 where you can actually see the default stuff I did not want to apply.
So as it is gone now, maybe it is not too bad (though it's sad to see the cool styling of input elements being “lost” or I again need to copy Mozilla source code for that… 🙃