Fixed labeled menu icon button icon positioning.

A .button.labeled within .ui.menu > .item has icon vertically aligned closer to bottom, not middle.

This fixes it.

src/collections/menu.less

@@ -1787,6 +1787,9 @@
 .ui.menu .item {
   font-size: 1rem;
 }
+.ui.menu:not(.vertical) .item > .button.labeled > .icon {
+  padding-top: 0.6em;
+}
 .ui.vertical.menu {
   width: 15rem;
 }