[FIX] point_of_sale: put PoS picking sequence in noupdate

The default PoS picking sequence should not be reset.
Losing custom configuration can lead to errors.

For instance:
- A customer initially uses the default sequence until POS09999
- he changes it to another one of his own taste starting the
  sequence over, like: WH/POS/00001
- In a module update, the sequence is reset and then we get the POS
  prefix again.
- In the next picking, we could have a duplicated name, and an error
  would raise in the Point of Sale.

opw 1962302
closes #32299

closes odoo/odoo#32842

Signed-off-by: Nans Lefebvre (len) <len@odoo.com>