Fix CI rendering in tensor point cloud notebook

Author: ssheorey

docs/jupyter/t_geometry/pointcloud.ipynb

@@ -14,7 +14,15 @@
     "import open3d as o3d\n",
     "import open3d.core as o3c\n",
     "import numpy as np\n",
-    "import matplotlib.pyplot as plt"
+    "import matplotlib.pyplot as plt\n",
+    "import os\n",
+    "import sys\n",
+    "\n",
+    "# Only needed for the tutorial: monkey-patch visualization.\n",
+    "sys.path.append(\"..\")\n",
+    "import open3d_tutorial as o3dtut\n",
+    "# Change to True to interact with visualization windows locally.\n",
+    "o3dtut.interactive = not \"CI\" in os.environ"
    ]
   },
   {