The SAFT report test suite was updated to use clearer sample data and correct expected values for amounts and invoice numbers. This helps ensure financial export reports for supported countries are validated more accurately without changing day-to-day user workflows.

-Improve the tests understanding by creating explicit data.
-Fix the tests comparing data with wrong amounts / invoice numbers.
-Improve the test coverage by using AssertXmlTreeEqual.
-Remove redundant code about XSD validation.