MAGETWO-34520: [UI] Updates messaging styles.

- Minor QA updates

Author: Oleg Zinoviev

app/design/adminhtml/Magento/backend/web/css/override.less

@@ -1407,8 +1407,10 @@ table.table tbody tr:last-child td {
   border: 0;
   color: #007bdb;
   content: '\e61a';
-  font: 400 1.9rem 'Admin Icons';
+  font-family: 'Admin Icons';
+  font-size: 1.9rem;
   font-style: normal;
+  font-weight: 400;
   height: auto;
   left: 1.9rem;
   line-height: inherit;
@@ -1445,9 +1447,9 @@ table.table tbody tr:last-child td {
   display: none;
 }
 .message-spinner .spinner {
-  position: absolute;
   font-size: 2.5rem;
   left: 1.5rem;
+  position: absolute;
   top: 1.5rem;
 }
 .message-in-rating-edit {

app/design/adminhtml/Magento/backend/web/css/source/_messages.less

@@ -60,8 +60,10 @@
         border: 0;
         color: @alert-icon__notice__color;
         content: @alert-icon__notice__content;
-        font: @alert__font-weight @alert-icon__font-size @alert-icon__font-name;
+        font-family: @alert-icon__font-name;
+        font-size: @alert-icon__font-size;
         font-style: @alert__font-style;
+        font-weight: @alert__font-weight;
         height: auto;
         left: 1.9rem;
         line-height: inherit;
@@ -111,9 +113,9 @@
         display: none;
     }
     .spinner {
-        position: absolute;
         font-size: @alert__spinner__font-size;
         left: 1.5rem;
+        position: absolute;
         top: 1.5rem;
     }
 }