Bug 21176: Fix due date calculation when high holds and TimeFormat is 12hr

Bug 21176: Fix due date calculation when high holds and TimeFormat is 12hr

What we were doing was wrong and is still wrong. The output_pref should not be done
in modules or script, only template side.
Much more work would be needed to clean the situation. This patch provides less changes
as possible to, hopefully, not introduce side-effects.

To recreate:
1 - Enable decreaseLoanHighHolds, set to 1 day and more than 0 holds
2 - Set TimeFormat to 12 hour
3 - Find or create a record with two items
4 - Place a hold on one of them
5 - Checkout the other to a different patron
6 - Note the warning message display correct time
7 - Confirm the checkout
8 - Note the item is due at 11:59AM

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>