Update SebastianLague channel description and add avatar image

Author: nikita2003

channelsExtended.json

@@ -3,7 +3,7 @@
     "full_name": "SebastianLague",
     "link": "https://www.youtube.com/@SebastianLague",
     "title": "SebastianLague",
-    "description": "Sebastian Lague YouTube channel explores complex programming and simulation topics—like physics, AI, and procedural generation—through visually rich, creative coding projects.",
+    "description": "Sebastian Lague explores complex programming and simulation topics—like physics, AI, and procedural generation—through visually rich, creative coding projects.",
     "avatar_thumbnail":"/yedidya-dev-picks/logos/SebastianLague.jpeg"
   },
   "TechGym": {