[e.cash] Use a different source for the twitter image

Summary: The twitter image is still not showing properly. Could be because of cloudfare. Can try a differnet source for it to see if that helps

Test Plan: Deploy the change and see if the image appears properly when shared via twitter

Reviewers: #bitcoin_abc, bytesofman

Reviewed By: #bitcoin_abc, bytesofman

Differential Revision: https://reviews.bitcoinabc.org/D14452