Add __setstate__ for BaseException (#7987)

Author: pranavrajpal

stdlib/builtins.pyi

@@ -1678,6 +1678,7 @@ class BaseException:
     __suppress_context__: bool
     __traceback__: TracebackType | None
     def __init__(self, *args: object) -> None: ...
+    def __setstate__(self, __state: dict[str, Any] | None) -> None: ...
     def with_traceback(self: Self, __tb: TracebackType | None) -> Self: ...
     if sys.version_info >= (3, 11):
         # only present after add_note() is called