[BUGFIX] Fix indexed_search page browsing calculation

Fix the calculation of pages shown by the indexed_search page browsers
to avoid negative page numbers or numbers exceeding the maximum available
page number.

Resolves: #60346
Releases: master, 6.2
Change-Id: I97de1c1afe42e29d450733f6741bca049f9803f6
Reviewed-on: http://review.typo3.org/31632
Reviewed-by: Markus Klein <klein.t3@reelworx.at>
Tested-by: Markus Klein <klein.t3@reelworx.at>