Fix #1108: Make sure youtube.onReady doesn't run twice

src/js/plugins/youtube.js

@@ -239,6 +239,10 @@ const youtube = {
                     triggerEvent.call(player, player.media, 'ratechange');
                 },
                 onReady(event) {
+                    // Bail if onReady has already been called. See issue #1108
+                    if (is.function(player.media.play)) {
+                        return;
+                    }
                     // Get the instance
                     const instance = event.target;