The phishing detection page had been using a separate stylesheet from
the rest of MetaMask. This stylesheet (`app/fonts/index.css`) was just
responsible for importing all fonts.
The phishing page now uses the same stylesheet as the rest of MetaMask.
The old stylesheet has been removed, leaving us with one less thing we
need to maintain as fonts are changed. We may want to revisit this
later to optimize performance by reducing the size of this CSS bundle
to the minimal set of styles required, but the impact is tiny in
practice, and not especially important in this situation.