[e.cash] Update hero links

Summary:
The two boxes on the right in the hero section are links. I think the avalanche
one would be better to link to the avalanche section below instead of an external site
off the rip. And the other one Im not sure what that would link to so removing the link
unless there is a suggestion

the grid component change is to prevent interferance with the pointer events

Test Plan: preview and check

Reviewers: #bitcoin_abc, bytesofman

Reviewed By: #bitcoin_abc, bytesofman

Subscribers: bytesofman

Differential Revision: https://reviews.bitcoinabc.org/D18523