test(pt_expt): pin smooth off in neighbor-list dpa1 fixture (route parity)

neighbor_list=None now takes the carry-all graph default for eligible
attention models; explicit World-1 builders take the legacy dense route.
With smooth attention the two routes differ by design (PR-D), so the
route-equivalence tests pin smooth_type_embedding=False.

Author: Han Wang

source/tests/pt_expt/utils/test_neighbor_list.py

@@ -113,6 +113,11 @@
         "temperature": 1.0,
         "set_davg_zero": True,
         "type_one_side": True,
+        # smooth attention diverges between the carry-all graph default
+        # (neighbor_list=None) and the explicit World-1 builders by design
+        # (NeighborGraph PR-D: dense keeps sel-padding in the attention
+        # softmax denominator); pin smooth off so all routes are exact.
+        "smooth_type_embedding": False,
         "seed": 1,
     },
     "fitting_net": {"neuron": [8, 8], "resnet_dt": True, "seed": 1},