chore: migrate back to react

[SethFalco]

A chore to switch back from Preact to React.

Overall, Preact was nice as it reduces the bundles, however, I've opted to switch back as:

• It didn't cover enough of the React implementation it seems. For example, during a cookie banner test, the web application would crash with Preact. I knew there would be differences, but seems we've started hitting some of them.
• The plan was to drop Preact when Docusaurus v4 came out anyway, as Docusaurus v4 would use React features that Preact does not intend to implement.
• To drop our little hacks.