Handle video being null in skip notice

Resolves #2201

Author: ajayyy

src/components/SkipNoticeComponent.tsx

@@ -697,7 +697,7 @@ class SkipNoticeComponent extends React.Component<SkipNoticeProps, SkipNoticeSta
     getFullDurationCountdown(index: number): () => number {
         return () => {
             const sponsorTime = this.segments[index];
-            const duration = Math.round((sponsorTime.segment[1] - getCurrentTime()) * (1 / getVideo().playbackRate));
+            const duration = Math.round((sponsorTime.segment[1] - getCurrentTime()) * (1 / (getVideo()?.playbackRate ?? 1)));
 
             return Math.max(duration, Config.config.skipNoticeDuration);
         };