status/bluetooth: Fix bluetooth placeholder text alignment

The padding specified for .bt-menu-placeholder was overridden by the
more specific.popup-menu-item:ltr/rtl padding. Also the ornament, was
still taking up space, as well as the spacing between the ornament and
the text.

Closes: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/6434
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2687>

data/theme/gnome-shell-sass/widgets/_quick-settings.scss

@@ -144,7 +144,7 @@
   .popup-menu-icon { -st-icon-style: symbolic; }
 }
 
-.bt-menu-placeholder {
+.bt-menu-placeholder.popup-menu-item {
   @extend %title_4;
   text-align: center;
 

js/ui/status/bluetooth.js

@@ -252,6 +252,7 @@ class BluetoothToggle extends QuickMenuToggle {
             ellipsize: Pango.EllipsizeMode.NONE,
             line_wrap: true,
         });
+        this._placeholderItem.setOrnament(PopupMenu.Ornament.HIDDEN);
         this.menu.addMenuItem(this._placeholderItem);
 
         this._deviceSection.actor.bind_property('visible',