Bug 29232: Clean up obsolete jQueryUI datepicker code from cash register stats template

Bug 29232: Clean up obsolete jQueryUI datepicker code from cash register stats template

This patch removes some jQueryUI datepicker code from
reports/cash_register_stats.tt which was left behind by Bug 28949.

To test, apply the patch and go to Reports -> Cash register statistics
wizard. The "From" and "To" date fields should work correctly, since
Flatpickr code is unchanged.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>