fix(ads): Fix the skip ad button not being clickable shaka-project#3284…

… (shaka-project#3326)

ui/less/ad_controls.less

@@ -21,32 +21,30 @@
   }
 }
 
-.shaka-server-side-ad-container {
-  .fill-container();
-
-  &:not([ad-active="true"]) {
-    pointer-events: none;
-  }
-}
-
-.shaka-client-side-ad-container {
+.shaka-client-side-ad-container, .shaka-server-side-ad-container {
   .absolute-position();
-}
 
-.shaka-controls-container {
   /* IMA SDK adds their own ad UI into an iframe element.
    * Adjust its position to fit in with our UI, when
    * Shaka UI is enabled. */
   iframe {
     .shaka-video-container[shaka-controls="true"] & {
       /* This moves the iframe up a little bit, so it
        * doesn't operlap with our controls. */
-      height: 92%;
-      z-index: 1;
+      height: 90%;
     }
   }
 }
 
+.shaka-server-side-ad-container {
+  .fill-container();
+  .shrinkable();
+
+  &:not([ad-active="true"]) {
+    pointer-events: none;
+  }
+}
+
 .shaka-ad-controls {
   .hide-when-shaka-controls-disabled();