Merge branch 'develop' into fix/6130-include-query-string-when-clearing-cache

Author: Jeroen-1978

assets/js/wpr-admin.js

@@ -17,10 +17,11 @@
 
 		const iframe = document.getElementById('rocketcdn-iframe');
 		const loader = document.getElementById('wpr-rocketcdn-modal-loader');
-		
-		iframe.addEventListener('load', function() {
-			loader.style.display = 'none';
-		});
+		if ( iframe && loader ) {
+			iframe.addEventListener('load', function() {
+				loader.style.display = 'none';
+			});
+		}
 	} );
 
 	window.addEventListener( 'load', () => {