PLT-3869 Fix set default language when user logs out (#3796)

webapp/actions/global_actions.jsx

@@ -457,6 +457,7 @@ export function emitUserLoggedOutEvent(redirectTo) {
             PreferenceStore.clear();
             UserStore.clear();
             TeamStore.clear();
+            newLocalizationSelected(global.window.mm_config.DefaultClientLocale);
             browserHistory.push(rURL);
         },
         () => {