ACP2E-71: Shifting of the PDP main image

- Updated gallery.less CSS file to not shift image after it has been loaded on product details page only for screen min-width 768.

Author: Mohan Ahuja

lib/web/mage/gallery/gallery.less

@@ -781,7 +781,10 @@
         max-height: 100%;
         max-width: 100%;
         position: absolute;
-        top:49.5%;
+        top: 50%;
+        @media all and (min-width: 768px) {
+            top:49.5%;
+        }
         .fotorama-translate3d(-50%, -50%, 0);
         transition-duration: @fotorama-fullscreen-zoom-time;
         transition-property: width, height, top, left;