[FIX] account: fix traceback happened in accounting dashboard

For Odoo Fin purpose:
When you click on Synchronize Now, you get a traceback.
This traceback comes from the "_get_journal_bank_account_balance"
method which performs a "self._cr.execute(...)" and a "self._cr.fetchone()".
However, it is possible that the orm may invalidate the whole
thing in the meantime because other calls are made.
This fix corrects this by grouping the "execute" of the "fetchone".

closes odoo/odoo#57555

X-original-commit: 7ab664bd8be72add3591895ef058afe7a1a9147e
Signed-off-by: Laurent Smet <smetl@users.noreply.github.com>

addons/account/models/account_journal.py

@@ -691,11 +691,11 @@ class AccountJournal(models.Model):
             FROM ''' + tables + '''
             WHERE ''' + where_clause + '''
         '''
-        self._cr.execute(query, where_params)
 
         company_currency = self.company_id.currency_id
         journal_currency = self.currency_id if self.currency_id and self.currency_id != company_currency else False
 
+        self._cr.execute(query, where_params)
         nb_lines, balance, amount_currency = self._cr.fetchone()
         return amount_currency if journal_currency else balance, nb_lines