(core) Update video tour

Summary: The embed id of the video tour now points to the new introduction video.

Test Plan: Manual.

Reviewers: jarek

Reviewed By: jarek

Differential Revision: https://phab.getgrist.com/D4049

app/client/ui/OpenVideoTour.ts

@@ -14,7 +14,7 @@ const t = makeT('OpenVideoTour');
 
 const testId = makeTestId('test-video-tour-');
 
-const VIDEO_TOUR_YOUTUBE_EMBED_ID = 'qnr2Pfnxdlc';
+const VIDEO_TOUR_YOUTUBE_EMBED_ID = '56AieR9rpww';
 
 /**
  * Opens a modal containing a video tour of Grist.