Cannot access protected property Drupal\search_api\Plugin\views\query\SearchApiQuery::$where in civicrm_entity_views_query_alter

Problem

After installing this module, and having Search API in the site, when I go to a page that has a view that uses a search index I get the error:

The website encountered an unexpected error. Please try again later.
Error: Cannot access protected property Drupal\search_api\Plugin\views\query\SearchApiQuery::$where in civicrm_entity_views_query_alter() (line 505 of modules/contrib/civicrm_entity/civicrm_entity.module).
civicrm_entity_views_query_alter(Object, Object)
call_user_func_array('civicrm_entity_views_query_alter', Array) (Line: 403)
Drupal\Core\Extension\ModuleHandler->invokeAll('views_query_alter', Array) (Line: 537)

Steps to reproduce

1. Create a view that uses a Search API index and place it somewhere in your site.
2. Enable the civicrm_entity module.
3. Go to see the view results.
4. The site breaks with the error shown before.

Proposed resolution

Check what class corresponds to the query and get the conditions depending on it, so that if it is Drupal\search_api\Plugin\views\query\SearchApiQuery then we use the method getWhere, otherwise we access the property directly.