Bug 24434: Submit on print slip

Bug 24434: Submit on print slip

This patch ensures that the print slip option on the WrongTransfer modal
also submits the form and thus triggers the actual transfer of the item.

We also prevent a double transfer submission (and thus a cancellation
line appearing in the branchtransfers table) for the case where a
transfer back home is triggered.

Signed-off-by: Victor Grousset/tuxayo <victor@tuxayo.net>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>