This update refines the way payment lines are handled within the restaurant POS module. The team has switched to a more modern, camelCase naming convention for payment methods, enhancing the system's internal structure and aligning with current development standards. This change ensures smoother and more efficient payment processing.

In this commit:
- Use the new method names in the payment adjustment flow.
- Replace deprecated snake_case methods with their camelCase equivalents for payment lines, payment terminals, and order totals.

Task:6049128

Forward-Port-Of: odoo/odoo#271792