Remove redundant method override because phpcs doesn't like it - can replace...

Remove redundant method override because phpcs doesn't like it - can replace with an issue (also shoudl probably be hook_requirements() so the form submission doesn't make an http request.

src/Form/LmsXapiSettingsForm.php

@@ -54,13 +54,4 @@ final class LmsXapiSettingsForm extends ConfigFormBase {
     return parent::buildForm($form, $form_state);
   }
 
-  /**
-   * {@inheritdoc}
-   */
-  public function validateForm(array &$form, FormStateInterface $form_state) {
-    // @todo try connecting to some LRS status endpoint to check
-    // if credentials are correct here.
-    parent::validateForm($form, $form_state);
-  }
-
 }