When an online payment provider is activated, Odoo now automatically assigns the appropriate outstanding account to the payment method it creates. This keeps online payment setup consistent with invoicing rules and reduces manual accounting configuration for integrated providers.

In this PR:
- When activating an Online Payment provider that creates a payment.method.line in a journal, automatically assign an Outstanding account to the payment method.

- Uses the existing Outstanding Account resolution method from Invoicing module to ensure consistency across the system.

- Applied to all Online Payment Providers that rely on provider integration, excluding manual payment providers without external integrations.

task-4826385

Australian payroll rule parameters have been updated for the 2025 period to keep payroll calculations aligned with current requirements. This helps businesses using Australian payroll process payslips with the latest applicable values.