[9.x] Make Vite::hotFile() public

[Jubeki]

Hey!

I often encounter the Problem while developing that I run into an error and then I need to manually reload the page after correcting the error. Using ViteJS it is already possible to reload the page automatically on file save and I would love it, if there is a way for auto reloading the error page to check if the code is running correctly.

For that I added the ability to add custom HTML to the error page in spatie/ignition#161

There is already a followup PR for adding the Vite Reload Script to the Error Page Head in spatie/laravel-ignition#110

While doing the PR I saw, that the hotFile method is protected, which is needed for detecting the correct file path. (Otherwise only a fallback to the public path hot-file is possible)

This PR makes the hotFile method public.