Changed color from #9e9e9e to #575757 for Delete and Move icons

Author: nishant04412

app/design/adminhtml/Magento/backend/web/css/source/components/_media-gallery.less

@@ -23,7 +23,7 @@
 @image-gallery-placeholder__height: 150px;
 @image-gallery-placeholder__width: @image-gallery-placeholder__height;
 
-@image-gallery-icons__color: @color-gray62;
+@image-gallery-icons__color: @color-gray34;
 @image-gallery-icons__hover__color: @color-gray52;
 
 @image-gallery-action__z-index: @image-gallery-image-hidden__z-index + 1;