fix: add pragma for pytest.raises branch that never falls through

The pytest.raises context manager always expects the exception; the
fall-through branch (no exception) is never taken.

Github-Issue:#1811

Author: skyvanguard

tests/issues/test_1811_sse_disconnect_hang.py

@@ -156,7 +156,7 @@ async def test_client_receives_error_on_sse_disconnect(slow_server_url: str):
 
             # Call the slow tool - the read timeout should fire
             # and the client should receive an error instead of hanging
-            with pytest.raises(McpError, match="SSE stream disconnected"):
+            with pytest.raises(McpError, match="SSE stream disconnected"):  # pragma: no branch
                 await session.call_tool("slow_tool", {})