[BUGFIX] Pagination wrong in IndexedSearch

Fix variable type issues in IndexedSearch pagination.
(classic and extbase VH)

This will ensure the CSS classes are correct again for current page and
next/prev page.

Resolves: #63350
Releases: master, 6.2
Change-Id: I6db4f2850ca9adc9d0aa07e908fc613036071676
Reviewed-on: http://review.typo3.org/34646
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Markus Klein <klein.t3@reelworx.at>
Tested-by: Markus Klein <klein.t3@reelworx.at>