[Cashtab] Revamp UX and remove antd from SignVerifyMsg

Summary:
Depends on D15844

Improve the SignVerifyMsg ux using new custom components.

Test Plan:
npm test

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Subscribers: emack

Differential Revision: https://reviews.bitcoinabc.org/D15846