Edit warning failed image upload style, added vars

Author: dazvolt

app/design/adminhtml/Magento/backend/Magento_ProductVideo/web/css/source/_module.less

@@ -236,8 +236,8 @@
 }
 
 .image-upload-error {
-    background: lighten(@color-red9, 80%);
-    color: #303030;
+    background: #F9E1E1;
+    color: @color-gray19;
     font-size: 12px;
     font-weight: 400;
     padding: 7px 7px 7px 35px;