Reorder imports in tests/test_model.py

Move 'from helpers.utils import random_mip_1' below the pyscipopt imports to group third-party and local imports (style-only change; no functional impact).

Author: Zeroto521

tests/test_model.py

@@ -3,9 +3,9 @@
 
 import numpy as np
 import pytest
-from helpers.utils import random_mip_1
 
 from pyscipopt import SCIP_BRANCHDIR, SCIP_PARAMSETTING, SCIP_STAGE, Model, quicksum
+from helpers.utils import random_mip_1
 
 
 def test_model():