some pyright type fixes

nerfstudio/scripts/render.py

@@ -455,7 +455,7 @@ class BaseRender:
     """If true, checks line-of-sight occlusions when computing camera distance and rejects cameras not visible to each other"""
     camera_idx: Optional[int] = None
     """Index of the training camera to render."""
-    kill_flag: Optional[List[bool]] = field(default_factory=lambda: [False])
+    kill_flag: List[bool] = field(default_factory=lambda: [False])
     """Stop execution of render if set to True."""
 
     def kill(self) -> None:

nerfstudio/viewer/export_panel.py

@@ -40,7 +40,7 @@ def populate_export_tab(
         def _(_) -> None:
             control_panel.crop_viewport = crop_output.value
 
-    server.add_gui_markdown("<small>Export available after a checkpoint is saved (default minimum 2000 steps)</small>")
+    server.gui.add_markdown("<small>Export available after a checkpoint is saved (default minimum 2000 steps)</small>")
     with server.gui.add_folder("Splat"):
         populate_splat_tab(server, control_panel, config_path, viewing_gsplat)
     with server.gui.add_folder("Point Cloud"):

nerfstudio/viewer/render_panel.py

@@ -1067,7 +1067,7 @@ def populate_render_tab(
             disabled=True,
         )
 
-    def _write_json() -> json:
+    def _write_json() -> Path:
         num_frames = int(framerate_number.value * duration_number.value)
         json_data = {}