[Cashtab] Upgrade testing-library/react-hooks

Summary:
Upgrade @testing-library/react-hooks

Looking to make better use of this lib for testing the useWallet hook. Want to have the latest version first.

Test Plan: npm test

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D15332