Comment 6 for bug 1976542

So to sum, it looks like what needs to happen is:

- Fixing the handling of navigating to the last page of results when eg-holds-grid is in prefetch mode
- Verifying that that also fixes the issue with 'Print Full List' that Garry found
- Fixing how the holds count is calculated in non-prefetch mode, either by doing a count of relevant holds when the grid is opened or, if the act of counting would be too expensive, adjusting the display of the count to make it clear that the total number is uncertain
- In non-prefetch mode, seeing if we can better detect whether the last page of results is in fact the last (when the total number of holds is an integral multiple of the page size)