0005558: Greeting Card with price not listed on billing.pdf -> bill is not correct!

Adding additional check if giftcard cost is not empty when checking if this price has to be added.
Fixing formatting of giftcard price when no wrapping is in the basket.
(cherry picked from commit 28fd1b2)
(cherry picked from commit c7d65c3)
(cherry picked from commit d960b6e)