[e.cash] Add media link to blog post

Summary: Some of our blog post were originally authored/posted by other outlets. Adding a link to these posts based on if its present and a valid url in the strapi data

Test Plan:
Run the app and find some blog posts that have this link. Check out the line under the title looks good and the link works
Also check it is not rendered on normal posts
Here are some for example that have a media link

/blog/how-blockchain-will-change-the-way-we-work-play-and-stay-healthy-in-the-future
/blog/gnc-shines-amid-high-profile-bitcoin-dev-resignations
/blog/is-there-a-future-for-cryptocurrencies-without-privacy-features

also run npm run test to run new tests

Reviewers: #bitcoin_abc, bytesofman

Reviewed By: #bitcoin_abc, bytesofman

Subscribers: bytesofman

Differential Revision: https://reviews.bitcoinabc.org/D14453