Of course, for an XML that is imported or exported the type of the
invoice will be different: vendor bill for import, customer invoice
for export e.g.  But in the case of vendor bill reverse charge we create
the XML from the vendor bill, but we did not think straight about how
it should be imported.

We did not expect it to be imported, but somehow in a database it was the
case and we see it is actually corresponding to a vendor bill coming from
a foreign vendor, so it would be better as well to import it as such.  Also
those types are only needed as vendor bills/refunds in our system.  (only
support bill for the moment)

opw-2977126

closes odoo/odoo#100530

Signed-off-by: Quentin De Paoli <qdp@odoo.com>