[e.cash] Modify static announcment bar

Summary:
Adding the static announcement bar back in with the same text from the final countdown, as no longer need
to fetch the api and calculate countdown status. Made tweak to use children instead of text prop as well to be more
flexible with multiple lines, icons, styles etc if needed

Test Plan: The site will materially look the same, but if you check the network traffic it wont be calling the api anymore

Reviewers: #bitcoin_abc, bytesofman

Reviewed By: #bitcoin_abc, bytesofman

Subscribers: bytesofman

Differential Revision: https://reviews.bitcoinabc.org/D14794