Fix js error in workflow-buttons.js (#32292)

Author: Fedik

build/media_source/com_workflow/js/admin-items-workflow-buttons.es6.js

@@ -39,6 +39,11 @@ Joomla.toggleAllNextElements = (element, className) => {
 
   document.addEventListener('DOMContentLoaded', () => {
     const dropDownBtn = document.getElementById('toolbar-status-group');
+
+    if (!dropDownBtn) {
+      return;
+    }
+
     const transitions = [].slice.call(dropDownBtn.querySelectorAll('.button-transition'));
     const headline = dropDownBtn.querySelector('.button-transition-headline');
     const separator = dropDownBtn.querySelector('.button-transition-separator');