(js) Don't change user language when not changed

Fixes #4244

UI/MainUI/SOGoRootPage.m

@@ -535,6 +535,11 @@
   return [[context resourceLookupLanguages] objectAtIndex: 0];
 }
 
+- (NSString *) localizedLanguage
+{
+  return [self labelForKey: [self language]];
+}
+
 - (NSArray *) languages
 {
   return [[SOGoSystemDefaults sharedSystemDefaults] supportedLanguages];

UI/Templates/MainUI/SOGoRootPage.wox

@@ -57,7 +57,9 @@
               <md-icon>language</md-icon>
               <md-input-container class="md-flex">
                 <label><var:string label:value="choose"/></label>
-                <md-select ng-model="app.creds.language" ng-change="app.changeLanguage($event)">
+                <md-select ng-model="app.creds.language"
+                           var:placeholder="localizedLanguage"
+                           ng-change="app.changeLanguage($event)">
                   <var:foreach list="languages" item="item">
                     <md-option var:value="item">
                       <var:string value="languageText"/>

UI/WebServerResources/js/Main/Main.app.js

@@ -17,9 +17,11 @@
       this.creds = {
         username: $window.cookieUsername,
         password: null,
-        language: $window.language,
         rememberLogin: angular.isDefined($window.cookieUsername) && $window.cookieUsername.length > 0
       };
+      // Send selected language only if user has changed it
+      if (/\blanguage=/.test($window.location.search))
+        this.creds.language = $window.language;
       this.loginState = false;
 
       // Show login once everything is initialized