Downgrade react-test-renderer

Summary: The version used require react 17, but numerous other package support only react up to 16.

Test Plan: Observe there is one less conflict when upgrading

Reviewers: #bitcoin_abc, josephroyking

Reviewed By: #bitcoin_abc, josephroyking

Subscribers: josephroyking

Differential Revision: https://reviews.bitcoinabc.org/D8809