[FIX] pos_adyen: JS error in loop if deleted Adyen payment line

Before this commit:
 If we remove a payment line using an Adyen payment method,
 `pending_adyen_line()` return `undefined`.
 With the `_poll_for_response` still being executed,
 it will pop some JS traceback each call with:
 ```js
 TypeError: Cannot read properties of undefined (reading 'terminalServiceId')
 ```

After this commit:
 No JS traceback loop

OPW-3032391

closes odoo/odoo#105716

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