fix(py): Pass 'project_name' to _get_parent_run method (langchain-ai#1927)

Using `trace` context manager with "parent" argument (dotted_order) in a
project that is not the default is not working due to this little
missing parameter.

Co-authored-by: Jacob Lee <jacoblee93@gmail.com>

Author: yakir-nevona

python/langsmith/run_helpers.py

@@ -1002,6 +1002,7 @@ def _setup(self) -> run_trees.RunTree:
                 "parent": self.parent,
                 "run_tree": self.run_tree,
                 "client": client_,
+                "project_name": self.project_name,
             }
         )