Upgrade to React 18

[nelsonni]

React 18 was released on March 29, 2022. There are several new features (including some breaking changes) including:

• Automatic Batching
• Transitions
• Suspense
• New Client and Server Rendering APIs
• New Strict Mode Behavior
• New Hooks (including useId, useTransition, useDeferredValue, useSyncExternalStore, and useInsertionEffect).

We should follow the official How to Upgrade to React 18 guide for upgrading to React 18. Additionally, reZach/secure-electron-template project already uses React 18 in a similar fashion to Synectic so we can leverage them as an example.

[nelsonni]

Updated to using React 18's Client Rendering APIs (i.e. createRoot) in ae84053.

Updated testing suite to remove @testing-library/react-hooks and migrate renderHook imports directly from @testing-library/react in 4e20eaf. Per the A Note about React 18 Support message on the @testing-library/react-hooks README:

As part of the changes for React 18, it has been decided that the renderHook API provided by this library will instead be included as official additions to both react-testing-library (testing-library/react-testing-library#991) and react-native-testing-library (callstack/react-native-testing-library#923) with the intention being to provide a more cohesive and consistent implementation for our users.