Issue #2989675 by e0ipso: Remove 'advancedOptionsIcon' from exported config entities

src/Form/JsonapiResourceConfigForm.php

@@ -402,7 +402,6 @@ class JsonapiResourceConfigForm extends EntityForm {
     ];
 
     $overrides_form['advancedOptionsIcon'] = [
-      '#type' => 'item',
       // Here we are just printing an arrow.
       '#markup' => '↳'
     ];