gui: Fix Firefox bookmark favicon (fixes #9506)

Firefox uses the last specified favicon link for bookmarks,
but only if it is available on initial page load.
Remove the second link and change the href of the favicon instead.

gui/default/index.html

@@ -12,8 +12,7 @@
   <meta charset="utf-8"/>
   <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
   <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
-  <link rel="shortcut icon" href="assets/img/favicon-default.png" type="image/x-icon"/>
-  <link rel="shortcut icon" href="assets/img/favicon-{{syncthingStatus()}}.png" type="image/x-icon"/>
+  <link id="favicon" rel="shortcut icon" href="assets/img/favicon-default.png" type="image/x-icon"/>
   <link rel="mask-icon" href="assets/img/safari-pinned-tab.svg" color="#0882c8"/>
 
   <title ng-bind="thisDeviceName() + ' | Syncthing'"></title>

gui/default/syncthing/core/syncthingController.js

@@ -11,6 +11,7 @@ angular.module('syncthing.core')
         var navigatingAway = false;
         var online = false;
         var restarting = false;
+        var favicon = $('#favicon');
 
         function initController() {
             LocaleService.autoConfigLocale();
@@ -1291,7 +1292,7 @@ angular.module('syncthing.core')
             return 'info';
         };
 
-        $scope.syncthingStatus = function () {
+        function syncthingStatus() {
             var syncCount = 0;
             var notifyCount = 0;
             var pauseCount = 0;
@@ -1360,6 +1361,10 @@ angular.module('syncthing.core')
             return 'default';
         };
 
+        $scope.$watch(function () {
+            favicon.attr('href', 'assets/img/favicon-' + syncthingStatus() + '.png');
+        });
+
         $scope.deviceAddr = function (deviceCfg) {
             var conn = $scope.connections[deviceCfg.deviceID];
             if (conn && conn.connected) {