[8.x] Add onLastPage method to the Paginator

[johanvanhelden]

In short:
This PR adds a convenience method to the paginator to determine if we are on the last page.

Why:
There is a useful onFirstPage method but it lacks the opposite onLastPage method.

I was just writing some blade code for a Tailwind pagination component and without reading a any documentation onFirstPage worked.

Meaning, you can have the following code:

@if ($paginator->onFirstPage())

But for the last page, you need to call an unexpected hasMorePages method and reverse the logic, so it becomes:

@if (!$paginator->hasMorePages())

So not only did I encounter a blade error, because onLastPage did not exist, but also I had to reverse the logic.

This PR keeps things consistent by adding a onLastPage() so you can simple do:

@if ($paginator->onLastPage())

Which, in my mind, is a very logical thing to try after using onFirstPage without reading any documentation.

[taylorotwell]

Thanks for contributing to Laravel! ❤️