Entity remove form throws 3 warnings

Problem/Motivation

The module throws warnings in dblog trying to get values while rendering entity remove the form.

Steps to reproduce

- create entity type that will be referenced in inline entity form;
- create a content type;
- in the content type add the field of type "Entity reference revision";
- set the reference to the previously created entity;
- set the field widget to "Inline entity form - Complex';
- create a node of the newly created content type;
- add an entity with IEF Complex Widget Dialog;
- save the node;
- open node edit form;
- click on the entity remove button;
- check the Recent log messages.

Warning: Undefined array key "#ief_labels" in _process_ief_form() (line 130 of /var/www/html/web/modules/contrib/ief_popup/ief_popup.module)
#0 /var/www/html/web/core/includes/bootstrap.inc(347): _drupal_error_handler_real()
#1 /var/www/html/web/modules/contrib/ief_popup/ief_popup.module(130): _drupal_error_handler()
#2 /var/www/html/web/modules/contrib/ief_popup/ief_popup.module(77): _process_ief_form()
#3 /var/www/html/web/core/lib/Drupal/Core/Extension/ModuleHandler.php(562): ief_popup_field_widget_single_element_inline_entity_form_complex_form_alter()

Warning: Trying to access array offset on value of type null in _process_ief_form() (line 130 of /var/www/html/web/modules/contrib/ief_popup/ief_popup.module)
#0 /var/www/html/web/core/includes/bootstrap.inc(347): _drupal_error_handler_real()
#1 /var/www/html/web/modules/contrib/ief_popup/ief_popup.module(130): _drupal_error_handler()
#2 /var/www/html/web/modules/contrib/ief_popup/ief_popup.module(77): _process_ief_form()
#3 /var/www/html/web/core/lib/Drupal/Core/Extension/ModuleHandler.php(562): ief_popup_field_widget_single_element_inline_entity_form_complex_form_alter()

Warning: Undefined array key "#overriden" in _process_ief_form() (line 236 of /var/www/html/web/modules/contrib/ief_popup/ief_popup.module)
#0 /var/www/html/web/core/includes/bootstrap.inc(347): _drupal_error_handler_real()
#1 /var/www/html/web/modules/contrib/ief_popup/ief_popup.module(236): _drupal_error_handler()
#2 /var/www/html/web/modules/contrib/ief_popup/ief_popup.module(77): _process_ief_form()
#3 /var/www/html/web/core/lib/Drupal/Core/Extension/ModuleHandler.php(562): ief_popup_field_widget_single_element_inline_entity_form_complex_form_alter()