[SP] [105.13.5] fix: disable next-page button on the last page

[MatiasArriola]

Task: https://app.clickup.com/t/869czvkrw

Summary

The next-page button stays enabled on a full last page (e.g. 75 results / 15 per page), so users can click past the end into an empty page. The faulty heuristic (rowsPerPage > rowCountPage) predates #8, but #8 made it visible by adding the "Page X of Y" label. Users were seeing "Page 6 of 5" before the button disables.

Now that the backend returns pageCount, prefer currentPage >= pageCount and fall back to the heuristic only when
pageCount is unavailable.

Test plan

• Open a working list with a total that is an exact multiple of the page size (e.g. 75 / 15). On the last page, the next-page button is disabled.
• Open a working list whose last page is partial (e.g. 73 / 15). Last page still disables next correctly.
• Navigate forward/back across pages — counts and "Page X of Y" stay consistent.