feat(presence): re-introduce image resolving for other platforms (#9637)

* spotify, youtube, twitch
* regression born from misunderstanding in 9a6e691

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

packages/discord.js/src/structures/Presence.js

@@ -358,6 +358,12 @@ class RichPresenceAssets {
       switch (platform) {
         case 'mp':
           return `https://media.discordapp.net/${id}`;
+        case 'spotify':
+          return `https://i.scdn.co/image/${id}`;
+        case 'youtube':
+          return `https://i.ytimg.com/vi/${id}/hqdefault_live.jpg`;
+        case 'twitch':
+          return `https://static-cdn.jtvnw.net/previews-ttv/live_user_${id}.png`;
         default:
           return null;
       }