[FIX] pos: Too many customer display updates

Updates to the customer display were sent too often:
 - Twice when creating a new order
 - Twice when removing a payment line
 - Every time the status of a payment line with a terminal changed

closes odoo/odoo#40024

X-original-commit: b72b08cf
Signed-off-by: Quentin Lejeune (qle) <qle@odoo.com>