fix: add blank line before send_request method in session.py

Pre-commit end-of-file fixer requires a blank line between the except
block and the next method definition.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: g97iulio1609

src/mcp/shared/session.py

@@ -241,6 +241,7 @@ async def __aexit__(
             if collapsed is not eg:
                 raise collapsed from eg
             raise  # pragma: lax no cover
+
     async def send_request(
         self,
         request: SendRequestT,