js: Switch more boxes to new orientation property

There are two instances where we set the deprecated `vertical`
property with a `{vertical}` shorthand that escaped previous
greps; move those to the new `orientation` property too.

Fixes: b75b4abaf0 ("js: Set BoxLayout orientation")
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3618>

js/ui/userWidget.js

@@ -179,7 +179,7 @@ class UserWidget extends St.BoxLayout {
 
         super._init({
             styleClass,
-            vertical,
+            orientation,
             xAlign,
         });