[newsfeed] Suppress unsightly animation edge cases when there are 0 or 1 active news items (#3336)

When the newsfeed module has an items list of size 1, every
`updateInterval` the animation runs to transition from the active story
to itself. This is unsightly. This PR suppresses that.

To reproduce: configure newsfeed with a single news source,
`ignoreOldItems` true, a short `updateInterval` (e.g. 3000), and a
carefully-chosen small `ignoreOlderThan` lining up with the current
contents of your news source.

modules/default/newsfeed/newsfeedfetcher.js

@@ -5,6 +5,7 @@
  * MIT Licensed.
  */
 
+const crypto = require("node:crypto");
 const stream = require("node:stream");
 const FeedMe = require("feedme");
 const iconv = require("iconv-lite");
@@ -67,7 +68,8 @@ const NewsfeedFetcher = function (url, reloadInterval, encoding, logFeedWarnings
 					description: description,
 					pubdate: pubdate,
 					url: url,
-					useCorsProxy: useCorsProxy
+					useCorsProxy: useCorsProxy,
+					hash: crypto.createHash("sha256").update(`${pubdate} :: ${title} :: ${url}`).digest("hex")
 				});
 			} else if (logFeedWarnings) {
 				Log.warn("Can't parse feed item:");