In payment register wizard, when registering payments on invoices, the journal_id
selected in the view would sometimes be replaced by another on save because journal_id
was recalculated in _get_line_batch_key().
All journal_id default value logic moved in _compute_journal_id()
This is a major redesign of commit: https://github.com/odoo/odoo/commit/a3c3cd68329935896e4ebb1e853824de2009e16b related to task : 2524441
closesodoo/odoo#74942
X-original-commit: 69429365c2c490f8f15cd02ee4d1cbee9caa7524
Signed-off-by: William André (wan) <wan@odoo.com>