Run Autoprefixer after [31504].

This removes media queries for Opera < 12 and `-ms-animation`/`@-ms-keyframes` which was never (dev versions excluded) supported by IE.

see #31337.

git-svn-id: https://develop.svn.wordpress.org/trunk@31505 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/css/install.css

@@ -378,7 +378,6 @@ body.language-chooser {
  * HiDPI Displays
  */
 @media print,
-  (-o-min-device-pixel-ratio: 5/4),
   (-webkit-min-device-pixel-ratio: 1.25),
   (min-resolution: 120dpi) {