Issue #3513938: Enable layout paragraph button display under elements

Closes #3513938

css/builder.css

@@ -334,6 +334,7 @@ form.layout-paragraphs-builder-form .js-lpb-component-list {
   justify-content: center;
   transform: translateY(-50%);
   opacity: 0;
+  z-index: 80;
 }
 
 .lpb-enable__button {