[FIX] point_of_sale: recompute bank statement balance before validating session
[FIX] point_of_sale: recompute bank statement balance before validating session

Before this commit, the return flow in the pos would not work if closing the pos session intervened before the return payment registration.
The balance of the the statements was not updated before going to the validate step.

After this commit, we force the recomputing of the relevant fields (i.e. balance_end_real), to reflect reality and permitting validatioon afterwards

OPW 743763

Closes #17438

ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo