Fix position of discount on PDF with US letter format

htdocs/core/modules/commande/doc/pdf_einstein.modules.php

htdocs/core/modules/facture/doc/pdf_crabe.modules.php

htdocs/core/modules/propale/doc/pdf_azur.modules.php

...core/modules/supplier_invoice/pdf/pdf_canelle.modules.php

.../core/modules/supplier_order/pdf/pdf_muscadet.modules.php

...core/modules/supplier_proposal/doc/pdf_aurore.modules.php