D9 deprecated functions fixes

Hi I stumbled an error when upgrading the d8 field_pager to d9 version and the error is :

Error: Call to undefined function Drupal\field_pager\Plugin\Field\FieldFormatter\pager_find_page() in Drupal\field_pager\Plugin\Field\FieldFormatter\EntityReferencePager->viewElements() (line 102 of /app/web/modules/contrib/field_pager/src/Plugin/Field/FieldFormatter/EntityReferencePager.php)

Error: Call to undefined function Drupal\field_pager\pager_default_initialize() in Drupal\field_pager\PagerHelper::mergeView()

adding a patch to fix the issues

hope this can help someone that is having the same issues as me