PB-265: Video background for Banner

- fix slider transform issue in admin

Author: omiroshnichenko

app/code/Magento/PageBuilder/view/adminhtml/web/css/source/content-type/slide/_default.less

@@ -129,6 +129,7 @@
 
         &.jarallax {
             .video-overlay {
+                -webkit-transform: unset;
                 z-index: 1;
             }