add shadow kwargs

Author: sentrivana

sentry_sdk/scope.py

@@ -1228,6 +1228,7 @@ def start_streamed_span(
         name: str,
         attributes: "Optional[Attributes]" = None,
         parent_span: "Optional[StreamedSpan]" = None,
+        **kwargs,   # TODO: remove, just for expediting seer testing
     ) -> "StreamedSpan":
         # TODO: rename to start_span once we drop the old API
         if parent_span is None: