fix: add no branch pragma for async context manager coverage issue

Author: felixweinberger

tests/shared/test_progress_notifications.py

@@ -371,7 +371,9 @@ async def handle_list_tools() -> list[types.Tool]:
     with patch("mcp.shared.session.logging.error", side_effect=mock_log_error):
         transport = InMemoryTransport(server)
         async with transport.connect() as (read_stream, write_stream):
-            async with ClientSession(read_stream=read_stream, write_stream=write_stream) as session:
+            async with ClientSession(  # pragma: no branch
+                read_stream=read_stream, write_stream=write_stream
+            ) as session:
                 await session.initialize()
                 # Send a request with a failing progress callback
                 result = await session.send_request(