Bug 28482: Refresh line from DB to get stored value

Before checking if the amount is 0 we get the stored value from the DB. This
ensures any amounts beyond the 6 digit precision we store will be removed.

To test:
1 - Add a processing fee of 15 to an itemtype
2 - Add an item of that type, set the replacement fee to 12.63
3 - Set MarkLostItemsAsReturned to 'On payment' only
4 - Set  WhenLostChargeReplacementFee to 'Charge'
5 - Checkout the item to a patron
6 - Mark the item lost
7 - Reload patron and confirm they are charged 27.63
8 - Go to accounting, pay amount, pay 27.63
9 - Item is still lost and not returned
10 - Apply patch
11 - Checkin the item
12 - Checkout to another patron
13 - Mark lost
14 - Patron charged 27.63
15 - Pay amount, 27.63
16 - Item returned!

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
(cherry picked from commit c4e2f4c718)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
(cherry picked from commit 1739543148)
Signed-off-by: Victor Grousset/tuxayo <victor@tuxayo.net>

Koha/Account/Line.pm

@@ -503,6 +503,7 @@ sub apply {
             if ( $self->credit_type_code ne 'FORGIVEN' && $debit->is_renewable ) {
                 $debit->renew_item( { interface => $params->{interface} } );
             }
+            $debit->discard_changes; # Refresh values from DB to clear floating point remainders
 
             # Same logic exists in Koha::Account::pay
             if (