fix(ambient-mode): fix ambient-mode not working for videos after restart (#2294)

* Fix Ambient Mode not working for videos after restart (#2255)

This should fix https://github.com/th-ch/youtube-music/issues/1641

* fix: fix waitForElement

---------

Co-authored-by: craftgeil <80261988+craftgeil@users.noreply.github.com>

src/utils/wait-for-element.ts

@@ -0,0 +1,11 @@
+export const waitForElement = <T extends Element>(selector: string): Promise<T> => {
+  return new Promise<T>((resolve) => {
+    const interval = setInterval(() => {
+      const elem = document.querySelector<T>(selector);
+      if (!elem) return;
+
+      clearInterval(interval);
+      resolve(elem);
+    });
+  });
+};