fix(clientSetup) : fix react installation and initialization code.

[arsadii]

Help for beginners to start using inertia-js with react.

• Adding the react and react-dom installation to make it clear that people need to install it.
• Adding import from react in initialization app.jsx to make it run.

[PedroAugustoRamalhoDuarte]

Good change @arsadii, i confirm the installation is working with this changes

[reinink]

Hey!

So our installation instructions have never included directions on how to install React, Vue, or Svelte — only how to get Inertia up and running.

I mostly did this because I didn't want the Inertia docs to have to explain a bunch of stuff that is better found in the docs for these particular frameworks. In the same way we don't explain how to setup Vite or webpack.

That said, I do kind of agree that this change would be nice if all it means is updating the dependencies and doesn't require any extra instructions. But if we're going to do that we need to update this for all the libraries (Vue 2, Vue 3, Svelte), not just React.

Feel free to update this PR to do that, otherwise I'll try and do it when I have a moment.