Revert "Remove position:relative in embedded CSS (#1122)"

This reverts commit 563bee916a97101b3a5e972a5d04317fbb3b9d78.

sass/_embedded.scss

@@ -8,6 +8,7 @@
 
     bottom: auto;
     height: 100%; // When embedded, it fills the containing element
+    position: relative;
     right: auto;
     width: 100%;