[10.x] Use HtmlString in Vite fake

[jasonvarga]

The change in #49150 has started to break our test suite.

Since that PR, the faked Vite instance now implements Htmlable, so we're now seeing a lot of Call to member function toHtml() on string from this line:

framework/src/Illuminate/Foundation/Vite.php

Line 784 in 1e03a4a

return $this->__invoke($this->entryPoints)->toHtml();

Since toHtml() is expecting __invoke to return an HtmlString, that's what this PR is doing.

We don't use the @vite directive (the error doesn't happen if you do). We use the facade essentially like this:

{{ Vite::withEntryPoints(['path/to/file.css']) }}

For the test I just slapped on ->toHtml() the same way you do that in https://github.com/laravel/framework/blob/10.x/tests/Foundation/FoundationViteTest.php

[jasonvarga]

Thanks for the quick turnaround.