Remove various google fonts leftovers

Seems like the fonts.css specifically was breaking some SW usage, so
good to fix that!

Author: pimterry

custom-typings/@beyonk__google-fonts-webpack-plugin.d.ts

@@ -5,7 +5,6 @@
     <meta name="robots" content="noindex">
     <base href="/" />
     <link rel='shortcut icon' type='image/x-icon' href='https://httptoolkit.com/favicon.ico' />
-    <link rel='stylesheet' href='/fonts.css' />
     <meta name="viewport" content="width=device-width">
     <title>HTTP Toolkit</title>
     <style>