Fix Safari detection for showing timestamps

src/app.ts

@@ -144,7 +144,7 @@ angular.module('3ema', [
     function($log: ng.ILogService, CONFIG: threema.Config, browserService: BrowserService) {
         // For Safari (when in DEBUG mode), monkey-patch $log to show timestamps.
 
-        if (!(CONFIG.DEBUG && browserService.getBrowser().isSafari)) {
+        if (!(CONFIG.DEBUG && browserService.getBrowser().isSafari(false))) {
             return;
         }