Single vlan handling fix

[po1vo]

glpi-injector fails with
Loading test.xml...ERROR: 500 Internal Server Error, array_is_list(): Argument #1 ($array) must be of type array, string given, called in /glpi/vendor/glpi-project/inventory_format/lib/php/Converter.php on line 1421
on the following data:

        <PORT>
          <VLANS>
            <VLAN>
              <NAME>default</NAME>
              <NUMBER>1</NUMBER>
            </VLAN>
          </VLANS>
        </PORT>

[trasher]

Please provide an example file that can be added to conversion tests. There are already VLANS example in tests/data/6.xml file that looks like the same you give as example data.

[po1vo]

Never mind, our xml file was corrupted and triggered the error.