Issue #3271312: Do not disable $strictConfigSchema in testing

tests/src/Functional/FillPdfSettingsFormTest.php

@@ -19,14 +19,6 @@ class FillPdfSettingsFormTest extends BrowserTestBase {
 
   use TestFillPdfTrait;
 
-  /**
-   * Set to FALSE to suppress checking all configuration saved.
-   *
-   * @var bool
-   * @see \Drupal\Core\Config\Development\ConfigSchemaChecker
-   */
-  protected $strictConfigSchema = FALSE;
-
   /**
    * {@inheritdoc}
    */