Aqbanking online transfer: Disable the non-SEPA verification rules for SEPA transactions.

Eventually, the SEPA rules need to be implemented, but for now we
just allow any alphanumerics.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@22786 57a11ea4-9604-0410-9ed3-97b8803252fd