style(mcp): format import statements and tuple definition for improved readability

Author: ppcantidio

pydantic_ai_slim/pydantic_ai/mcp.py

@@ -388,10 +388,7 @@ def _transport_client(
     async def client_streams(
         self,
     ) -> AsyncIterator[
-        tuple[
-            MemoryObjectReceiveStream[SessionMessage | Exception],
-            MemoryObjectSendStream[SessionMessage],
-        ]
+        tuple[MemoryObjectReceiveStream[SessionMessage | Exception], MemoryObjectSendStream[SessionMessage]]
     ]:  # pragma: no cover
         if self.http_client and self.headers:
             raise ValueError('`http_client` is mutually exclusive with `headers`.')