[e.cash] Fix font imports

Summary: The fonts were not loading properly due to incorrect src path. Updated them

Test Plan:
npm run dev or @bot preview-e.cash
check the browser console, you should not see any errors about the fonts not loading

Reviewers: #bitcoin_abc, bytesofman

Reviewed By: #bitcoin_abc, bytesofman

Subscribers: bytesofman

Differential Revision: https://reviews.bitcoinabc.org/D13898