Revert "[landing] SIWE component with RainbowKit that connects & signs a message"

Summary:
This reverts commit 4dd1bf70caab7877a3c7b9108fbdbc3c90b24952 (SIWE) while we get to the bottom of the cool looking issue caused by rainbowkit
video:
relevant context:

Test Plan: ran it before reverting and after. fixes CSS issue

Reviewers: abosh, ashoat

Reviewed By: abosh

Subscribers: tomek, atul, ashoat, abosh

Differential Revision: https://phab.comm.dev/D4971