[e.cash] Move button ID down

Summary:
The CSS Id needs to be on the link for Google tag manager to pick it up on click
This will allow us to track very specific buttons, as opposed to any clicks on x link

Test Plan: preview the site and check the button id on hero landing

Reviewers: #bitcoin_abc, bytesofman

Reviewed By: #bitcoin_abc, bytesofman

Subscribers: bytesofman

Differential Revision: https://reviews.bitcoinabc.org/D16642