Top navigation bar should expand with content.

When the breadcrumbs stack vertically the header should expand vertically
as well. Otherwise, the breadcrumbs float outside the header. This
rearrangement happens when the screen is minimized horizontally, and the breadcrumbs change from
horizontal to vertical layout.

src/core_plugins/kibana/public/management/styles/main.less

@@ -13,7 +13,7 @@ kbn-management-objects-view {
 }
 
 nav.navbar {
-  height: 70px;
+  min-height: 70px;
 }
 
 .tab-management {