Fix doubling hash in React StrictMode

[TomKalina]

Hello!

We are having the following problem in our application.

We are using <React.StrictMode> in the application, this causes the application to redirect twice in dev mode. This forces us to double the previous hash during development because it calls the same router logic twice. For example it makes exanple.com/#hi become exanple.com/#hi#hi after the update

This fix would prevent that from happening. If so, would you have handled this differently?

Thank you very much for Inertia! It's a cool project 😉