Remove Deprecated functions

Problem/Motivation

On a fresh Drupal 10.3.5 install, right after creating a register and going to /admin/commerce/pos/main, 3 errors are shown:

1. Deprecated function: Creation of dynamic property Drupal\Core\Form\FormState::$wrapper_id is deprecated in Drupal\commerce_pos\Form\POSForm->buildOrderForm() (line 175 of modules/contrib/commerce_pos/src/Form/POSForm.php).
2. Deprecated function: Creation of dynamic property Drupal\commerce_pos\Plugin\Field\FieldWidget\PosOrderItemWidget::$is_edit_order is deprecated in Drupal\commerce_pos\Plugin\Field\FieldWidget\PosOrderItemWidget->formElement() (line 225 of modules/contrib/commerce_pos/src/Plugin/Field/FieldWidget/PosOrderItemWidget.php).
3. Deprecated function: Creation of dynamic property Drupal\commerce_pos\Plugin\Field\FieldWidget\PosOrderItemWidget::$initial_items_on_order is deprecated in Drupal\commerce_pos\Plugin\Field\FieldWidget\PosOrderItemWidget->formElement() (line 227 of modules/contrib/commerce_pos/src/Plugin/Field/FieldWidget/PosOrderItemWidget.php).

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes