Do not pickle functions of Blockwise

pytensor/tensor/blockwise.py

 from collections.abc import Sequence
+from copy import copy
 from typing import Any, Optional, cast
 
 import numpy as np
@@ -87,6 +88,11 @@ class Blockwise(Op):
         self._gufunc = None
         super().__init__(**kwargs)
 
+    def __getstate__(self):
+        d = copy(self.__dict__)
+        d["_gufunc"] = None
+        return d
+
     def _create_dummy_core_node(self, inputs: Sequence[TensorVariable]) -> Apply:
         core_input_types = []
         for i, (inp, sig) in enumerate(zip(inputs, self.inputs_sig)):