fix error of build:prod

src/client/styles/scss/_sidebar.scss

@@ -48,7 +48,7 @@
   // override @atlaskit/navigation-next styles
   $navbar-total-height: $grw-navbar-height + $grw-navbar-border-width;
   div[class$='-LayoutContainer'] {
-    height: calc(100vh - $navbar-total-height);
+    height: calc(100vh - #{$navbar-total-height});
     margin-top: $navbar-total-height;
   }
   div[class$='-NavigationContainer'] {