Accept YouTube /live/ and /shorts/ URLs in extractVideoId

The video-id regex only matched /watch?v=, youtu.be, /embed/, and /v/
forms, so youtube.com/live/<id> and youtube.com/shorts/<id> links were
rejected with "Invalid YouTube URL". Add both forms to the server and
frontend extractors (kept in sync) and cover them with tests.

Ship as 0.2.159.

public/index.html

@@ -2714,7 +2714,7 @@
 
     function extractVideoId(url) {
       const patterns = [
-        /(?:youtube\.com\/watch\?v=|youtu\.be\/|youtube\.com\/embed\/|youtube\.com\/v\/)([a-zA-Z0-9_-]{11})/,
+        /(?:youtube\.com\/watch\?v=|youtu\.be\/|youtube\.com\/embed\/|youtube\.com\/v\/|youtube\.com\/live\/|youtube\.com\/shorts\/)([a-zA-Z0-9_-]{11})/,
         /^([a-zA-Z0-9_-]{11})$/,
       ];
       for (const p of patterns) {