[FIX] point_of_sale: add rank to customer on sale

It is a partial revert of the commit: https://github.com/odoo/odoo/commit/36c05f5e056794d68c363343e267c592bd9bce31
because the behavior has been fixed in stable in commit https://github.com/odoo/odoo/commit/577dac5baee5e503baba9f30dff67e69daafa00b
almost at the same time.

So no need of double increade the ranking of a sale in the POS.

closes odoo/odoo#42397

Signed-off-by: pimodoo <pimodoo@users.noreply.github.com>

addons/point_of_sale/models/pos_order.py

@@ -367,20 +367,6 @@ class PosOrder(models.Model):
 
         self.write({'state': 'paid'})
 
-        if self.partner_id:
-            try:
-                with self.env.cr.savepoint():
-                    self.env.cr.execute("SELECT 'customer_rank' FROM res_partner WHERE ID=%s FOR UPDATE NOWAIT",
-                                        (self.partner_id.id,))
-                    self.env.cr.execute("UPDATE res_partner SET customer_rank = customer_rank +1 WHERE ID=%s",
-                                        (self.partner_id.id,))
-                    self.env.cache.remove(self.partner_id, self.partner_id._fields['customer_rank'])
-            except psycopg2.DatabaseError as e:
-                if e.pgcode == '55P03':
-                    _logger.debug('Another transaction already locked partner rows. Cannot update partner ranks.')
-                else:
-                    raise e
-
         return True
 
     def action_pos_order_invoice(self):