Fix HUB link https://ultralytics.com/hub (#13120)

Refactor code for speed and clarity

tutorial.ipynb

@@ -253,7 +253,7 @@
       "source": [
         "# 3. Train\n",
         "\n",
-        "<p align=\"\"><a href=\"https://bit.ly/ultralytics_hub\"><img width=\"1000\" src=\"https://github.com/ultralytics/assets/raw/main/im/integrations-loop.png\"/></a></p>\n",
+        "<p align=\"\"><a href=\"https://ultralytics.com/hub\"><img width=\"1000\" src=\"https://github.com/ultralytics/assets/raw/main/im/integrations-loop.png\"/></a></p>\n",
         "Close the active learning loop by sampling images from your inference conditions with the `roboflow` pip package\n",
         "<br><br>\n",
         "\n",