data: Ship local copy of a cog wheel icon

Closes https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/8135

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3589>

js/gdm/loginDialog.js

@@ -319,7 +319,7 @@ const SessionMenuButton = GObject.registerClass({
     _init() {
         let button = new St.Button({
             style_class: 'login-dialog-button login-dialog-session-list-button',
-            icon_name: 'emblem-system-symbolic',
+            icon_name: 'cog-wheel-symbolic',
             reactive: true,
             track_hover: true,
             can_focus: true,

js/ui/messageTray.js

@@ -1306,7 +1306,7 @@ export function getSystemSource() {
     if (!systemNotificationSource) {
         systemNotificationSource = new Source({
             title: _('System'),
-            iconName: 'emblem-system-symbolic',
+            iconName: 'cog-wheel-symbolic',
         });
 
         systemNotificationSource.connect('destroy', () => {