React 18 Upgrade

[brian-smith-tcril]

Required for openedx/frontend-app-learning#1587

• Update react peer dependencies to support React 18
• Update everything else (mostly RTL) to support React 18

[brian-smith-tcril]

I'm going to close this as not planned for now. The peer dependency update unblocked the frontend-app-learning upgrade to React 18. If any issues are found with the upgrade we can reopen this or make new issues to address them.