Fix CI errors (#9810)

Fixes ci error introduced by:
* #9804

Author: abey79

examples/python/notebook/set_application_blueprint.ipynb

@@ -43,12 +43,8 @@
     "\n",
     "os.environ[\"RERUN_NOTEBOOK_ASSET\"] = \"inline\"\n",
     "\n",
-    "import numpy as np\n",
-    "import pandas as pd\n",
-    "import pyarrow as pa\n",
     "import rerun as rr\n",
-    "import rerun.blueprint as rrb\n",
-    "from rerun.notebook import Viewer"
+    "import rerun.blueprint as rrb"
    ]
   },
   {

rerun_py/rerun_bindings/rerun_bindings.pyi

@@ -757,7 +757,7 @@ def set_callback_sink_blueprint(
     callback: Callable[[bytes], Any],
     make_active: bool,
     make_default: bool,
-    blueprint_stream: Optional[PyRecordingStream] = None,
+    blueprint_stream: Optional[PyRecordingStream],
 ) -> None:
     """Set callback sink for blueprint."""