MC-3507: Text on variable placeholder drops outside placeholder box when container is too small

- Fixed bug

Author: nathanjosiah

app/code/Magento/PageBuilder/view/adminhtml/web/css/source/_inline-wysiwyg.less

@@ -8,6 +8,10 @@
 //  _____________________________________________
 
 .inline-wysiwyg {
+    .magento-placeholder {
+        height: auto;
+        min-height: 20px;
+    }
     &.mce-edit-focus {
         outline: none;
     }