Removed inner black border for dashboard button

src/css/less/navbar.less

@@ -64,12 +64,10 @@
   font-weight: bold;
   color: #a2a2a2;
   border: 1px solid #555;
-
   a {
     display: inline-block;
     background: @grafanaTargetFuncBackground;
     padding: 5px 15px 5px 10px;
-    border: 1px solid #000;
     border-radius: 3px;
     color: #a2a2a2;