Fix pyright lints

Author: schloerke

shiny/_app.py

@@ -9,7 +9,6 @@
 from typing import Any, Callable, Literal, Mapping, Optional, TypeVar, cast
 
 import starlette.applications
-import starlette.exceptions
 import starlette.middleware
 import starlette.routing
 import starlette.websockets

shiny/ui/_page.py

@@ -14,7 +14,7 @@
 )
 
 from copy import copy
-from typing import Any, Callable, Literal, Optional, Sequence, cast
+from typing import Any, Callable, Literal, Optional, Sequence
 
 from htmltools import (
     MetadataNode,
@@ -752,7 +752,6 @@ def page_auto(
                 )
 
     # If we got here, _page_fn is not None, but the type checker needs a little help.
-    page_fn = cast(Callable[..., Tag], page_fn)
     return page_fn(*args, **kwargs)