Refs #31032 -- Removed unnecessary vendor prefixes from admin CSS.

The CSS properties have been standardized and are available in all
supported browsers.

django/contrib/admin/static/admin/css/dashboard.css

@@ -23,5 +23,4 @@ ul.actionlist li {
     list-style-type: none;
     overflow: hidden;
     text-overflow: ellipsis;
-    -o-text-overflow: ellipsis;
 }

django/contrib/admin/static/admin/css/login.css

@@ -55,8 +55,6 @@ body.login {
     clear: both;
     padding: 8px;
     width: 100%;
-    -webkit-box-sizing: border-box;
-       -moz-box-sizing: border-box;
     box-sizing: border-box;
 }
 

django/contrib/admin/static/admin/css/responsive.css

@@ -99,9 +99,7 @@ input[type="submit"], button {
     }
 
     #changelist-search > div {
-        display: -webkit-flex;
         display: flex;
-        -webkit-flex-wrap: wrap;
         flex-wrap: wrap;
         max-width: 480px;
     }
@@ -111,7 +109,6 @@ input[type="submit"], button {
     }
 
     #changelist #toolbar form #searchbar {
-        -webkit-flex: 1 0 auto;
         flex: 1 0 auto;
         width: 0;
         height: 22px;