Do not overlap layout by fallbackElement.

[valerii15298]

I wanna use lazy route property for code splitting to load element dynamically.
But when I click a link app is unresponsive and fallbackElement is not shown anywhere...
Also when I navigate to the nested route, when lazy is called, The only fallbackElement is shown without layout.
This is quite a problem(at least for me).

lazy Route property is simply unusable right now...
There is no point to use lazy if you cannot specify fallbackElement for it and still show parent's route layout when loading...
Reproduction: https://codesandbox.io/p/sandbox/determined-archimedes-t443gj?file=%2Fsrc%2FApp.tsx%3A19%2C15
Also in repro there are quite bunch of other bugs like showing nested rows in parent when it should not(not sure if it is because of codesandbox itself) and also when clicking on a link fallbackElement is not shown at all which is a horrible user experience!

For example using React's Suspense and React.lazy works perfectly and saves layout from parents rout:
Uncomment this lines in repro:

// const router = createBrowserRouter(
//   createRoutesFromElements(routesUsingSuspense)
// );

and comment this:

const router = createBrowserRouter(createRoutesFromElements(routes));

And you will see that everything works fine when using React's Suspense...