Bug 17556: Koha::Patrons - Remove GetHideLostItemsPreference

Bug 17556: Koha::Patrons - Remove GetHideLostItemsPreference

The subroutine C4::Members::GetHideLostItemsPreference can easily be
replaced with Koha::Patron->find(42)->category->hidelostitems

Test plan:
Create 2 patron categories, 1 with "Lost items in staff client" set to
"shown" and another one to "Hidden by default"
Create 2 patrons using them
On the result search page, the detail page of a record, the item list
page and the page to place a hold, make sure the lost items are
shown/hidden as expected

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>