Do not NULL lazyloaded props when redirecting back to the same page

[lpeterke]

Imagine a "Home" page that displays a long list of items, which are loaded using Inertia::lazy().

The "Home" page might also have a sidebar with a component that sends a simple POST, for example "Subscribe to our newsletter". After the action is performed, the NewsletterController might simply redirect back using return redirect()->back().

Inertia will then NULL (or whatever the default is) all page props that utilize Inertia::lazy(). However, this feels rather buggy, as we the are still on the same Page Component and nothing should temper with these lazyloaded props, until we trigger a new manual reload.

Previous discussion: #863