Calling get_class() without arguments is deprecated in Element/Disqus

Problem/Motivation

Deprecated function: Calling get_class() without arguments is deprecated in Drupal\Core\Render\ElementInfoManager->Drupal\Core\Render\{closure}() (line 132 of /var/www/html/web/core/lib/Drupal/Core/Render/ElementInfoManager.php)

#0 /var/www/html/web/core/includes/bootstrap.inc(166): _drupal_error_handler_real()
#1 /var/www/html/web/core/lib/Drupal/Core/Render/ElementInfoManager.php(132): _drupal_error_handler()
#2 [internal function]: Drupal\Core\Render\ElementInfoManager->Drupal\Core\Render\{closure}()
#3 /var/www/html/web/modules/contrib/disqus/src/Element/Disqus.php(25): get_class()

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes