[FIX] account: manual payment method

Commit 5439e72a introduces the automatic creation of a journal
for a payment provider. However, the journal created doesn't have a
default payment method, to avoid showing it in the backend.

In the case of the eCommerce with automatic invoice creation, this
set-up returns a 500 error after an online payment. Solving the problem
is not obvious for the end-user.

The error comes from the fact that the 'Manual' payment method is not
available on the journal. We can remove this check.

opw-1853011