Remove an extra argument in MPNNLSTM example

[RyushiAok]

fix MPNNLSTM example error related to commit 609148a

❯ python ./examples/recurrent/mpnnlstm_example.py
Traceback (most recent call last):
  File "D:\repo\RyushiAok\pytorch_geometric_temporal\examples\recurrent\mpnnlstm_example.py", line 32, in <module>
    model = RecurrentGCN(node_features = 4)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\repo\RyushiAok\pytorch_geometric_temporal\examples\recurrent\mpnnlstm_example.py", line 23, in __init__
    self.recurrent = MPNNLSTM(node_features, 32, 32, 20, 1, 0.5)
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: MPNNLSTM.__init__() takes 6 positional arguments but 7 were given