Skip favicon resize if it is a SVG containing a CSS media query

[capi1O]

Custom favicons can be passed as a panel icon and they can be SVGs containing dynamic CSS media queries in order to match device light mode (light or dark) for instance.

Sidebery by default redraws the favicon as a PNG, this fix skips this operation if it is a SVG containing a media query.

fixes #1937

Note: in addition to the fix I also renamed favicon variables names in order to emphasis the fact that they are base64 images because it was not clear in the code.

[mbnuqw]

Thank you

[capi1O]

Thank you for the merge!

I have one question though, just out of curiosity. It's something I did not understand about the function resizeFavicon

Clearly seeing the code below this function handles SVG favicons:

     const base64svgWithSize = Utils.setSvgImageSize(base64fav, ds, ds)
      if (!base64svgWithSize) return base64fav
      await Utils.setImageSrc(favRescaleImg, base64svgWithSize)
      sw = favRescaleImg.naturalWidth
      sh = favRescaleImg.naturalHeight

But what is the purpose of resizing the favicon if it is a SVG?

[mbnuqw]

In tests, it appeared that resized PNGs are smaller than SVGs (on average, based on real data). Plus, svg favicons can contain relatively large raster images (in base64).